FOR: hoi gar:

As in Romans 8:2-3, the conjunction for (1063) (gar) in this verse carries the meaning of because. Every time you see a "for" at the beginning of a sentence always stop and ask what is it there "for"? (see term of conclusion) It will usually be a term of conclusion and you will be forced to read the prior context to understand what is being explained.

S Lewis Johnson explains the "for" noting that...

In the fifth verse of the chapter the apostle gives the first of the reasons why believers walk after the Spirit. In other words, the "for" of the verse is connected with the last clause of the preceding verse. Men walk according to the inward inclination, bent, or disposition that they have. Thus, those who have at their inmost center the lusts of the flesh will walk after the flesh, while the opposite is true of those who walk according to the Spirit. To "be" after the flesh is to exist only for the flesh, and the clause, then, refers to the unbeliever. They mind the things of the flesh, that is, they think and will according to the desires of the flesh. Their conduct follows accordingly. On the other hand, they that "are" after the Spirit think and will according to inclinations implanted by Him in the inmost being of the believer. They are inclined to holiness, just as the unbelievers are inclined to unholiness. The renewed nature of the believer, upheld by the Spirit, determines the bent of the life. (Romans 8:5-17)

Paul's point is that a believer does not behave according to the flesh because their new heart and mind (cf Ezekiel 36:26, 27) are no longer continually centered on the things of the flesh and ruled by Sin.

Disciple's Study Bible concurs adding that...

The end result of following the bent of human nature is physical and spiritual death. People who yield their behavior to the sinful nature will never be pleasing to God. (Disciple's Study Bible)

Expositor's Bible Commentary observes that...

At this point Paul launches upon a fairly extended statement contrasting the terms "flesh" and "Spirit," which he has used in Ro 8:4. Both terms are difficult because they can have more than one meaning. For example, "flesh" can be used of ordinary physical life shared by believer and unbeliever alike (cf. 2Cor 10:3). But usually in Paul the ethical force of the word, referring to human nature as corrupted and weakened by sin, is dominant. Because the variety of expressions about the flesh may be confusing, some explanation is necessary. To be in the flesh, as the word is used here (Ro 8:8), is to be in the unregenerate state. To be (ontes, Ro 8:5) according to the flesh is to have the flesh as the regulating principle of one's life. To walk (peripatousin, Ro 8:4) according to the flesh is to carry out in conduct those things dictated by the flesh.

THOSE WHO ARE (continually) ACCORDING TO (dominated, controlled by) THE FLESH SET THEIR MINDS ON THE THINGS OF THE FLESH: hoi gar kata sarka ontes (PAPMSN) ta tes sarkos phronousin (3PPAI): (Ro 8:12,13; Jn 3:6; 1Cor 15:48; 2Cor 10:3; 2Pet 2:10) (6,7; Mk 8:33; 1Cor 2:14; Php 3:18,19)

For those who are according to the flesh and are controlled by its unholy desires set their minds on and pursue those things which gratify the flesh (Amplified)

Those who live by the corrupt nature have the corrupt nature’s attitude (GWT)

Those who live as their human nature tells them to, have their minds controlled by what human nature wants. (GNT)

Those who live following their sinful selves think only about things that their sinful selves want. (NCV)

For those who live according to the flesh have their outlook shaped by the things of the flesh (NET)

Those who live according to the sinful nature have their minds set on what that nature desires (NIV)

Those who are living by their natural inclinations have their minds on the things human nature desires (NJB)

Those who are dominated by the sinful nature think about sinful things (NLT)

For if men are controlled by their earthly natures, they give their minds to earthly things (Weymouth)

For those who are habitually dominated by the sinful nature put their minds on the things of the sinful nature (Wuest)

A MIND
DOMINATED BY
THE EVIL FLESH

Are (5607) (ontes) is in the present tense indicating that this is the general pattern of their life (their lifestyle) or habitual practice.

John Piper writes...

Before a person can perform the best of all acts, he must become a new person. Thorn bushes don’t produce figs, apple trees don’t produce olives, and a “natural man” does not produce faith. He cannot. Here is the way Paul put it in Romans 8:5, 6, 7...Fallen human nature is so hostile to God and his demands that it cannot submit to God in faith. We must be born again, born of the Spirit, before we can approve of God’s Word and trust Christ. (That Which is Born of the Spirit is Spirit)

H A Ironside writes that Paul reminds us...

that there are two exactly opposite principles, two utterly opposed standards of life, to be considered. They who are after (according to) the flesh - that is, the unsaved - are dominated by the fleshly nature. They "mind the things of the flesh." In these terse words the entire life of the natural man is summed up. In blessed contrast to this, those who live according to the Spirit of God - saved men and women - characteristically mind the things of the Spirit. Parenthetically Paul explained, the minding of the flesh is death, that is its only legitimate result; but the minding of the Spirit is life and peace. He who is thus Spirit-controlled is lifted onto a new plain where death has no place and conflict is not known. (Ironside, H. Romans).

According to (2596) (kata) conveys the root meaning of “down,” which in the present context suggests domination. In this context, the phrase according to refers to basic spiritual nature and indicates ones  fundamental essence, bent, or disposition. In short Paul is describing an unbeliever, devoid of the Spirit. An unbeliever orders his or her behavior in such a way that it is dominated or controlled by the flesh, the Sin nature inherited from Adam (Ro 5:12-note) which gives the unregenerate their propensity to commit sins.

As noted above (and the view favored by the majority of conservative commentaries) the plain sense of this verse favors that those who are according to the flesh are the unsaved, the unredeemed, the unregenerate as discussed below. As the apostle points out a few verses later, the unsaved not only are according to the flesh but are in the flesh and are not indwelt by the Holy Spirit, The saved, on the other hand, not only are according to the Spirit but are in the Spirit and indwelt by Him (Ro 8:9-note).

Set...mind (5426) (phroneo from phren = literally the diaphragm and thus that which curbs or restrains. Figuratively, phren is the supposed seat of all mental and emotional activity) refers to the basic orientation, bent, and thought patterns of the mind, rather than to the mind or intellect itself (that is the Greek word nous). Phroneo includes a person’s affections and will as well as his reasoning.  In other words phroneo refers not simply to intellectual activity but also to direction and purpose of heart.

Richards writes that phroneo...

in particular expresses the idea of thinking or judging in a neutral way. The context indicates the content of what is being thought. (Richards, L O: Expository Dictionary of Bible Words: Regency)

It means to to give careful consideration to something and thus to set one’s mind on, to be intent on or to have a mental disposition for, to keep on giving serious consideration to something, to ponder, to let one’s mind dwell on, to keep thinking about, to fix one’s attention on. (Col 3:2-note)

Vine comments that in Col 3:2 (note) phroneo

"signifies the whole action of the mind, not merely the thinking power, the reasoning, but the set purpose of the mind, and is thus used in a distinctly spiritual sense. (Vine, W. Collected writings of W. E. Vine. Nashville: Thomas Nelson )

Phroneo means to employ one’s faculty for thoughtful planning, with emphasis upon the underlying disposition or attitude. Phroneo leads one through the process of evaluating a situation and, on the basis of our evaluation, adopting an attitude or disposition to act (Php 2:5-note)

Phroneo can mean to have an opinion with regard to something, to think or to judge (1Cor 13:11, Acts 28:22).

Vincent remarks that phroneo...

denotes a general disposition of the mind rather than a specific act of thought directed at a given point.

Vine writes that phroneo means...

“to think,” “to form a judgment”; but in the New Testament never merely “to hold an opinion,” always it is contemplated that action will be taken upon the judgment formed, cp. Philippians 4:10 (note)...(phroneo)  implies moral interest or reflection, not mere unreasoning opinion. (Ibid )

Phroneo is used 28 times in the NAS (Matt 16:23; Mark 8:33; Acts 28:22 ; Ro 8:5; 11:20; 12:3, 16; 14:6; 15:5 ; 1Cor 13:11 ; 2Cor 13:11; Gal 5:10 ; Phil 1:7; 2:2, 5; 3:15, 19; 4:2, 10 ; Col 3:2) and is translated adopt...view, 1; conceited, 1; concern, 1; concerned, 1; feel, 1; have...attitude, 3; intent on...purpose, 1; live in harmony, 1; mind, 4; observes, 2; set their minds, 2; set your mind, 1; setting your mind, 2; think, 3; views, 1

Phroneo is found 7 times in the Septuagint (LXX) (Dt 32:29; Esther 8:12; Ps 94:8; Isa 44:18, 28; 56:10; Zech 9:2)

Note the present tense in Romans 8:5 depicts this action as the continual practice or mindset.  The object of their thinking and striving is fleshly. Their mind is continually regulated by the flesh. These are unbelievers whose basic disposition is to satisfy the cravings of their unredeemed flesh. They obey the impulses of the flesh. They live to gratify the desires of the corrupt nature. They cater to the body, which in a few short years will return to dust.

Mounce has an interesting comment noting that...

People’s decisions about how they intend to live determines how they think about things. Moral choice precedes and determines intellectual orientation. People do not think themselves into the way they act but act themselves into the way they think. Ethical decision, more often than misguided reason, lies at the heart of error. (Mounce, R. H. Romans: The New American Commentary. Broadman & Holman Publishers)

KJV Bible Commentary writes that phroneo...

means to have something as the habit of your thought; something in which you place a total interest. Those who place their total interest in the things of the flesh cannot have their interest in the things of God. (Dobson, E G, Charles Feinberg, E Hindson, Woodrow Kroll, H L. Wilmington: KJV Bible Commentary: Nelson)

Wuest comments that in Romans 8:5 phroneo

"speaks of a deliberate setting of one’s mind upon a certain thing. The unsaved person, habitually dominated by the indwelling sinful nature...(Phroneo) speaks of a deliberate setting of one’s mind upon a certain thing. The unsaved person is dominated by the evil nature habitually and as habitually puts his mind on those things that the sinful nature has always welling up within itself, the things of sin." (Wuest, K. S. Wuest's Word Studies from the Greek New Testament: Studies in the Vocabulary of the Greek New Testament: Grand Rapids: Eerdmans) (Bolding Added)

Paul uses phroneo in Philippians, where he tells the saints at Philippi

make my joy complete by being of the same mind, (phroneo) maintaining the same love, united in spirit, intent on one purpose (phroneo).... (and to) Have this attitude (phroneo - present imperative = habitually, command)) in yourselves which was also in Christ Jesus." (Php 2:2-note; Php 2:5-note)

Writing to the Colossians after having just presented two chapters of doctrine dealing with the supremacy of Christ Who is in them and is their hope (certainty) of glory, Paul exhorts the saints...

Set your mind (phroneo - present imperative = habitually, command) on the things above, not on the things that are on earth.  (Col 3:2-note)

Paul teaches elsewhere that the man who is living dominated or controlled by the flesh does not welcome the things of the Spirit writing that

a natural (psuchikos - governed by sensual appetites and living apart from the Spirit of God) man (born into Adam and not regenerated in Christ = still "in Adam", not "in Christ") does not (ou = absolute negation!) accept (dechomai = deliberately and readily, receive kindly, they do not "put out a welcome mat"! = present tense) the things of the Spirit of God (because the Truth of God given by the Spirit calls for a decision - "Am I going to continue to do it my way or God's way?"); for they are foolishness (moria = that which is considered intellectually weak, irrational. From "moros" dull, stupid >"moronic" = same word is used to describe the Gentiles who are perishing) to him, and he cannot (dunamai = present tense = have intrinsic power - natural men lack the inner, inherent ability and resources on their own to = absolutely lacks the inherent, internal enablement to) understand (ginosko = know by experience) them, because they are spiritually appraised (Sanakrino =  sift up and down and so to scrutinize, to examine accurately and carefully with exact research like in legal processes). (1Cor 2:14)

This individual neither comprehends God's Truth nor even desires to do so. To reiterate, phroneo speaks of a deliberate setting of one’s mind upon a certain thing. The unsaved person is dominated by the evil nature habitually and habitually sets their mind on those things that the sinful nature has always welling up within itself, the things of sin.

The basic disposition of an unredeemed, unregenerate person is one who continually chooses to

“indulge the flesh in its corrupt desires” (2Pe 2:10-note).

The flesh, the principle of rebellion within in man (see below), produces a certain pattern and way of thinking. Likewise, the Holy Spirit produces a certain pattern and way of thinking.

Unregenerate individuals (not born from above, not new creations in Christ) are...

"enemies of the cross of Christ, whose end is destruction, whose god is their appetite, and whose glory is in their shame, who set their minds (phroneo = present tense = continually) on earthly things." (Php 3:18, 19-note).

Alan Carr explains that...

The Desires Of The Mind Are Changed -The first thing Paul addresses is the contrast that exists between the natural mind of man and a mind that has been transformed by the Spirit of God. The whole idea here is that the natural bent, or orientation of the natural man's thinking is always directed toward the things that pertain to the flesh.

In other words, the carnal mind focuses on the physical, material and other selfish concerns. It may think about religion, but it will be a religion based in what he can do for himself. There may be thoughts about God, but that will be thoughts about how to approach God on his own terms. Generally, however, the carnal mind is filled with thoughts that center around ways to gratify the flesh. Of course, this is what the Bible teaches us about the lost man and his mind set, 2Pe 2:10 (note), "But chiefly them that walk after the flesh in the lust of uncleanness, and despise government. Presumptuous are they, self-willed, they are not afraid to speak evil of dignities." ; Phil. 3:19 (note), "Whose end is destruction, whose God is their belly, and whose glory is in their shame, who mind earthly things."

But, what a change is manifested in the lives of those who have been redeemed! While the saved do falter from time to time, their minds are filled with thoughts of heavenly things. These are people who love God and all the things that pertain to Him. They love His Word, His people, His house, His worship, etc. The Spirit of God redirects the thinking of those redeemed by the blood of Jesus.

A good question to ask ourselves at this point is, of what character are the thoughts that fill our minds? Depending upon how we answer that question, we can learn a lot about ourselves! (Sermon)

William Newell writes that...

The distinction between these two classes is as real as that between the sheep and goat nations at Christ's coming, or between those written in the book of life and those not written, at the last judgment. An unconquerable sadness rises in our hearts at the fact that after these centuries upon centuries of Divine dealing with man, and especially since the gospel has been preached, as Paul declares, "in all creation under heaven" (Col 1:23-note), there are yet those like Cain, Esau, Balaam, Saul, Judas, that are according to flesh. Alas, this description includes the mass of our race, for it is only "a little flock" that can be described as being according to Spirit.

Now all those according to flesh cherish, desire, are occupied with, and absorbed in, talk of, think of, follow after, the things of flesh; those according to Spirit, likewise discern, value, love, are absorbed in, the things of Spirit.

Those according to flesh "mind" the flesh's things: its physical lusts, gluttony, uncleanness, slothfulness; its soulical lusts, mental delights, pleasures of the imagination, esthetic indulgences or "tastes" whether art, music, sculpture, or what not; its spiritual lusts, of pride, envy, malice, avarice: in a word, every unclean thing, and every good thing used by unclean persons, that is, persons not cleansed by the blood of Christ, not new creatures in Him. Then, too, there is the "religion" of the flesh, which includes all not of and in the Holy Ghost.  (Romans 8: Expository Notes Verse by Verse)

Wayne Barber explains that

"What Paul is doing in this section is contrasting a LOST and a SAVED person - this may seem obvious but there are some respected commentaries and pastors who hold that Paul is simply referring to a saved man who is struggling with the FLESH. (we know that although we are no longer "in the flesh", the Bible clearly teaches that the flesh is still in us (see Sarx #4b), in these mortal bodies - the difference now that we are in Christ is that we can say "yes" to Jesus and "no" to the FLESH).

Those who "set their minds on the things of the flesh" are doing so as a lifestyle. This is the habit of their lives because the verb "set minds on" is in the present tense. "Set minds on" is the single Greek word phroneo which speaks of a mind devoted to something, a determined focus set on something and means more than just the mind that entertains thoughts, etc. It is a fixed mindset. It is all the person lives for. Those who are in Adam (a "in the flesh") live to gratify the strong impulses (desires) of their corrupt (in Adam0 nature and they know no other way. From birth because of their inherited Sin nature inherited from Adam their minds are continuously fixed on the things which are displeasing to God.

The contrasting mindset is the person who continually or habitually has their mind focused on the things of the Spirit. To help understand what has happened to the mind of a person who is now in Christ, let's look at a similar word (sophronismos) in 2Ti 1:7-note where Paul is exhorting young Timothy

"For God has not given us a spirit of timidity, but of power and love and discipline (KJV = sound mind = sophronismos)"

When I was in Adam my mind was fixed a certain way - it was on the "AM Radio Band" so to speak. When Christ came into my life and placed me in Christ, He "re-programmed" my mind to the "FM Band", a totally different focus now compared to when I was in Adam. The word for "discipline" (sophronismos) is derived from sozo meaning "salvation" and phren meaning "mind". Taken together the Greek word translated "discipline" pictures a man with a "saved" "mind" (in fact 1Co 2:16 says believers now "have the mind of Christ").

"When Christ rescued my dead spirit from in Adam and He took up residence in my body, He also rescued my mind and gave me a "saved mind" . When we were in Adam, there was only one way our mind could think and that was on the things of the flesh. When I came to Christ the Spirit changed my mind so to speak from "AM" to "FM". This doesn't' mean we won't occasionally drift back into "AM band thinking" and acting, but it does mean that because of repentance (a change of thinking that produces a change of direction in my life) there is now a general bent or orientation of our "saved mind" toward Christ and the things of the Spirit. And even when we stray off course, His Spirit chastens and disciplines and scourges and brings us back so that we continually set our minds on the things of God."

Godet writes that...

To be after the flesh, is to be inwardly governed by it, as the natural man always is. The part here referred to is the deepest source of the moral life, whence the will is constantly drawing its impulses and direction. Hence the consequence:  they are preoccupied with the things of the flesh, aspire after them. The word phroneo is one of those terms which it is difficult to render in French, because it includes at once thinking and willing.  (Godet, F L: The Epistle of St Paul to the Romans - ONLINE)

Moule comments that...

they who are flesh-wise, the unchanged children of the self-life, think, “mind,” have moral affinity and converse with, the things of the flesh; but they who are Spirit-wise, think the things of the Spirit, His love, joy, peace (The Epistle of Paul the Apostle to the Romans - ONLINE)

Cranfield writes...

We take Paul’s meaning in this verse then to be that those who allow the direction of their lives to be determined by the flesh are actually taking the flesh’s side in the conflict between the Spirit of God and the flesh, while those who allow the Spirit to determine the direction of their lives are taking the Spirit’s side. (Cranfield, C. E. B.  A Critical and Exegetical Commentary on the Epistle to the Romans . London; New York: T&T Clark International)

Robert Haldane adds this comment on phroneo noting that...

The word here translated “mind,” (KJV "For they that are after the flesh do mind -phroneo - the things of the flesh") includes both the understanding and the affections, and signifies the strong bent of the mind regarding the object desired. The minding of the flesh comprehends all the faculties of man in his unregenerate state, there being no power of the mind exempt from sin. If, then, a man walks according to the flesh, seeking acceptance with God by his own works, moral or ceremonial, however earnest or sincere he may be in his endeavors, he will remain under the prevalence and dominion of sinful appetites. Such persons have their minds intent on the things that gratify their corrupt nature. They have no relish for spiritual things; whatever they may be induced to do from dread of punishment, or hope of reward in a future world, their desires are, in reality, centered in the things of this world. Whatever may be their profession of religion, their hearts are supremely engrossed with earthly things (cf Php 3:19-note- whose end is destruction, whose god is their appetite, and whose glory is in their shame, who set their minds - continually - on earthly things ); and for these, if they could obtain their wish through eternity, they would gladly barter all the glories of heaven. In one word, they mind the things of the flesh, they love the world, and all that is in the world. “If any man love the world, the love of the Father is not in him. For all that is in the world, the lust of the flesh, and the lust of the eyes, and the pride of life, is not of the Father, but is of the world (1John 2:15-16).” (Romans 8 Commentary - ONLINE) (Bolding added)

Flesh (4561) (sarx) is used 147 times in the NT (in table below click book title for uses of sarx).  A simple definition of sarx is difficult because sarx has many nuances (e.g., some Greek lexicons list up to 11 definitions for sarx!). The diligent disciple must carefully observe the context of each use of sarx in order to accurately discern which nuance is intended. The range of meaning extends from the physical flesh (both human and animal), to the human body, to the entire person, and even to all humankind! Refer to the table below for the 4 basic definitions of sarx as categorized in Strong's Lexicon.

THE NT USES
OF SARX

Sarx - 147 uses in 126 verses in the NAS Note: Almost 10% of all NT uses of sarx in Romans 8! This chapter deserves special study if we would truly understand the flesh!:

Mt 16:17; 19:5, 6; 24:22; 26:41; Mk 10:8; 13:20; 14:38; Lk 3:6; 24:39; Jn 1:13, 14; 3:6; 6:51, 52, 53, 54, 55, 56, 63; 8:15; 17:2;

Acts 2:17, 26, 31;

Ro 1:3; 2:28; 3:20; 4:1; 6:19; 7:5, 18, 25; 8:3, 4, 5, 6, 7, 8, 9, 12, 13; 9:3, 5, 8; 11:14; 13:14;

1Co 1:26, 29; 5:5; 6:16; 7:28; 10:18; 15:39, 50; 2Co 1:17; 4:11; 5:16; 7:1, 5; 10:2, 3; 11:18; 12:7;

Gal 1:16; 2:16, 20; 3:3; 4:13, 14, 23, 29; 5:13, 16, 17, 19, 24; 6:8, 12, 13; Eph 2:3, 11, 14; 5:29, 31; 6:5, 12; Php 1:22, 24; 3:3, 4; Col 1:22, 24; 2:1, 5, 11, 13, 18, 23; 3:22; 1Ti 3:16; Philemon 1:16;

Heb 2:14; 5:7; 9:10, 13; 10:20; 12:9; Jas 5:3; 1Pe 1:24; 3:18, 21; 4:1, 2, 6; 2Pe 2:10, 18; 1Jn 2:16; 4:2; 2Jn 1:7; Jude 1:7, 8, 23; Rev 17:16; 19:18, 21

The NAS translates sarx as: (147) - bodily, 1; bodily condition, 1; body, 2; earth, 1; earthly, 1; fellow countrymen, 1; flesh, 129; fleshly, 4; life, 3; man, 1; mankind, 1; nation, 1; personally, 1.

Note that over 50% (75x) of the NT uses of SARX are by Paul. Note the concentration in Romans 22x and Galatians 16x.

Flesh in the moral/ethical or spiritual sense (see analysis of sarx below) as used by Paul in Romans 8:5 (and in many other passages - see box below) describes the outlook orientated toward self,  is prone to sin, is opposed to God and which pursues its own ends in self-sufficient, independence from God. Flesh is the ugly complex of human sinful desires that includes the ungodly motives, affections, principles, purposes, words, and actions that sin generates through our bodies. Sarx as used in this manner denotes the entire fallen human being—not just the sinful body but the entire being, including the soul and mind, as affected by sin. To live according to the flesh is to be ruled and controlled by that evil complex. Because of Christ’s saving work on our behalf, the sinful flesh no longer reigns over us, to debilitate us and drag us back into the pit of depravity into which we were all born.

Flesh in the moral/ethical or spiritual sense is that urge within us toward total autonomy and rebellion, toward being our own little gods accountable to no one, responsible to no one, obeying no one, respecting no one, and running our own little worlds to suit ourselves. It is that continual tug of self-centeredness and selfishness within each of us that keeps us from being completely His.

Born again believers need to understand that there is still this remnant of the flesh within our physical bodies of flesh. In contrast to the unregenerate man, believers now have the power led by the Holy Spirit to say "yes" to God and "no" to the flesh, whereas before Romans 6 (Ro 6:1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11-see notes on Ro 6:1-3; 6:4-5; 6:6-7; 6:8-10; 6:11) took place we had no choice. Paul teaches clearly that the flesh is opposed to Spirit. The unbeliever can live only in the flesh, but the believer can live in the Spirit but can fall back into living according to the Spirit. Paul repeatedly encourages believers to overcome the deeds of the flesh in the only way possible - by living in the Spirit.

To live according to the flesh is to be ruled and controlled by the flesh. Because of Christ’s saving work on our behalf, the sinful flesh no longer reigns over us, to debilitate us and drag us back into the pit of depravity into which we were all born.

J Vernon McGee has a simple classification for sarx writing that...

it can be used in three different ways. It can speak of the body, the physical body that we have, the meat that is on the bones. It can speak of weakness, meaning that which is psychological. It can also mean that corrupt nature which you and I have, that fallen nature. That is the spiritual meaning. So this word can be used in a physical sense, in a psychological sense, and in a spiritual sense.  Paul uses the word flesh in all three senses but more frequently in the sense of the old Adamic, fallen nature. (McGee, J V: Thru the Bible Commentary:  Nashville: Thomas Nelson)

John Piper defines flesh (in its moral/ethical sense) as

the old ego that is self-reliant and does not delight to yield to any authority or depend on any mercy. Flesh craves the sensation of self-generated power and loves the praise of men....in its conservative form it produces legalism -- keeping rules by its own power for its own glory.... (in its more liberal form) produces grossly immoral attitudes and acts (Gal 5:19, 20, 21-see notes Gal 5:19; 20; 21) The flesh is the proud and unsubmissive root of depravity in every human heart which exalts itself subtly through proud, self-reliant morality, or flaunts itself blatantly through self-assertive, authority-despising immorality. (Read John Piper's full sermon Walk By the Spirit!)

Harry Ironside writes that...

It is not that the flesh (referring to the moral/ethical meaning) is, or ever will be, in any sense improved. The flesh in the oldest and godliest Christian is as incorrigibly evil as the flesh in the vilest sinner...All efforts to reform or purify it are in vain. The law only demonstrates its incurable wickedness. And this explains why the natural man is so completely unprofitable... To say so would be to declare that man is not a responsible creature but is simply the victim of a hard, cruel fatalism. But although he knows the evil and approves the good, the natural man inclines toward the wrong and fails to do the right. Because he is dominated by the flesh, to which he yields his members as instruments of unrighteousness (Ro 6:13-note), he is powerless to change his nature. The natural man therefore cannot really please God." (Ironside, Harry. Romans and Galatians. Kregel. 2006) (Bolding added)

Larry Richards summarizes flesh (specifically the moral/ethical aspect) writing that...

"flesh" is a complex word with many meanings....The NT emphasizes humanity's moral inadequacy. When they are isolated from God, human beings are energized by evil desires and guided by perceptions that distort God's will and His nature. The word "flesh" reminds us that we are caught in the grip of sin. Even a desire for righteousness cannot enable us to actually become righteous. God deals with our flesh in a surprising way. He does not free us now from the fleshly nature. Instead, he provides a source of power that will release us from the domination of the flesh. Jesus has paid for sins generated by our flesh, whether sins of our past or those yet in our future. But Jesus has also provided us with his Holy Spirit. The Spirit lives within us, and He is the source of new desires and a new perspective. Even more, the spiritual power unleashed in the resurrection is made available to us in the Spirit...If we choose to rely on the Spirit and if we commit ourselves to His control, we will experience a resurrection kind of life--now. The limits imposed by our fleshly human nature will no longer contain us, and we will be freed from the mastery of the flesh." (Richards, L O: Expository Dictionary of Bible Words: Regency) (Bolding added)

Lewis Sperry Chafer wrote that flesh (the moral/ethical definition) is...

Any aspect of life or conduct which is undertaken in dependence upon the energy and ability of the flesh is, to that extent, purely legal in character, whether it be the whole revealed will of God, the actual written commandments contained in the Law, the exhortations of grace, or any activity whatsoever in which the believer may engage.

Middletown Bible Church has an instructive note on explaining that...

There are five things that will never happen to the flesh (referring to the moral/ethical aspect):

1) The flesh cannot be changed. The rebellious, non-submissive flesh will never be transformed into submissive, obedient flesh. God’s method of dealing with the flesh is not to change it but to CONDEMN IT (Ro 8:3-note) and crucify it (Gal 5:24-note; Gal 2:20-note and compare Ro 6:6-note).

2) The flesh cannot be reformed. It cannot be corrected or restored to purity. That which is corrupt remains corrupt. That which is desperately wicked remains desperately wicked (Jer 17:9). The Church was reformed (we speak of the Protestant "Reformation") and restored to some degree of purity but the flesh will never have a reformation. Two thousand years ago it did not have a reformation but it had a crucifixion!

3) The flesh can never be trained. The flesh is stubborn. It refuses to change its ways. It’s immutable. You can never teach the flesh how to please God. The flesh is incorrigible--incapable of being corrected or amended. The flesh refuses to change its ways. The works of the flesh always remain the same (Gal 5:19, 20, 21-see notes  Gal 5:19; 20; 21).

4) The flesh cannot be improved. It always remains as it is: depraved, corrupt, wicked, sinful, evil, anti-God, rebellious, stubborn, proud, etc.

5) The flesh cannot be reconciled to God. It is always and ever opposed to God (Gal 5:17-note). It will never be at peace with God; instead there is constant war. God can never be brought into harmony with that which is out of harmony with His holy and righteous character.

A Christian has an old nature from his physical birth and a new nature from his spiritual birth. The New Testament contrasts these two natures and gives them various names which are more or less synonyms:

Dearly beloved of God, be ever aware of the deceitfulness of sin's desire to use our unredeemed flesh to cause us to stray from the highway of holiness. As Spurgeon rightly reminds us...

Corruptions may slumber, but godliness must watch. So long as we live, the corruptions of the old nature will be ready to rise in rebellion, and they must be held down by divine grace working in us continual care. Quaint Berridge wisely says:—

And if the monsters round thy head
Lay harmless down, like sheep,
Yet never once surmise them dead,
They have but dropped asleep.

The Evangelical Dictionary of Biblical Theology has a good word regarding one's approach to the study of a word as complex as sarx...

The range of meanings borne by this term in the Bible starts from the literal use denoting the material of which the human body is chiefly constructed, but quickly takes on other senses derived from the writers’ understanding of the created order and its relation to God. Careful attention to context is needed to catch the precise nuance in any given case. (Elwell, W. A., & Elwell, W. A. The Evangelical Dictionary of Biblical Theology . Baker Book House)
 

BUT THOSE WHO ARE ACCORDING TO THE SPIRIT, THE THINGS OF THE SPIRIT: hoi de kata pneuma ta tou pneumatos: (Ro 8:9,14; 1Cor 2:14; Gal 5:22, 23, 24, 25; Eph 5:9; Col 3:1, 2, 3)

"but those who are according to the Spirit and are controlled by the desires of the Spirit set their minds on and seek those things which gratify the [Holy] Spirit." (Amplified)

"Those who live as the Spirit tells them to, have their minds controlled by what the Spirit wants" (GNT)

"But those who live following the Spirit are thinking about the things the Spirit wants them to do" (NCV)

"but those who live according to the Spirit have their outlook shaped by the things of the Spirit" (NET)

"But those who live in accordance with the Spirit have their minds set on what the Spirit desires." (NIV)

"those who live in the Spirit have their minds on spiritual things" (NJB)

"but those who are controlled by the Holy Spirit think about things that please the Spirit." (NLT)

"If they are controlled by their spiritual natures, they give their minds to spiritual things" (Weymouth)

"but those who are habitually dominated by the Spirit put their minds on the things of the Spirit" (Wuest)

A MIND
DOMINATED BY
THE HOLY SPIRIT

According to the Spirit describes the mind possessed by the Spirit and thus controlled and dominated by the Holy Spirit. These are believers, God's true children, because the Holy Spirit by Whom they were born, now indwells all of them. True believers rise above flesh and blood and live for those things that are eternal, the word of God, prayer, worship, evangelism, making of disciples, etc.

In other words, those who belong to God are concerned about godly things. As Jonathan Edwards liked to say, they have “holy affections,” deep longings after God and sanctification. As Paul has made clear in Romans 7, even God’s children (although not everyone agrees Paul is referring to believers in that section) falter in their obedience to Him. But they nevertheless “joyfully concur with the law of God in the inner man” (Ro 7:22-note). Despite their spiritual failures, the basic orientation of those who set their mind "according to the Spirit" is to seek those things that have to do with the Spirit.

In God’s eyes, there are only two kinds of people in the world, those who do not belong to Him and those who do. Obviously there are degrees in both categories. In other words, some unsaved people exhibit high moral standards and behavior, and, on the other hand, many saints do not mind the things of God as obediently as they should especially considering that they possess the Holy Spirit Who enables them to be holy. But every human being is completely in one spiritual state of being or the other and either belongs to God or does not belong to God. Just as a person cannot be partly dead and partly alive physically, neither can he be partly dead and partly alive spiritually. There is no middle ground. A person is either forgiven and in the kingdom of God or unforgiven and in the kingdom of darkness in this world and under the dominion of Satan. In short, every person on planet earth is either a child of God or a child of Satan, all are either in Christ or in Adam. No exceptions to this rule.

Note the four contrasts in (Romans 8:5-8):

In the flesh—in the Spirit (Ro 8:5-note)
Death—life (Ro 8:6-note)
War with God—peace with God (Ro 8:6, 7-note)
Pleasing self—pleasing God (Ro 8:8-note)

MacDonald comments on the contrast in this verse noting that...

Those who live according to the flesh—that is, those who are unconverted—are concerned with the things of the flesh. They obey the impulses of the flesh. They live to gratify the desires of the corrupt nature. They cater to the body, which in a few short years will return to dust.  But those who live according to the Spirit—that is, true believers—rise above flesh and blood and live for those things that are eternal. They are occupied with the word of God, prayer, worship, and Christian service. (MacDonald, W., & Farstad, A. Believer's Bible Commentary: Old and New Testaments. Nashville: Thomas Nelson)

One's predominant mindset will determine not only their eternity but also the quality of life now. Wesley Hager, (Conquering: Eerdmans, 1965) pictures this contrast poetically...

One ship drives east and another drives west
With the selfsame winds that blow.
’Tis the set of the sails
And not the gales
Which tells us the way to go.

Like the winds of the sea are the ways of fate,
As we voyage along through life—
’Tis the set of a soul
That decides its goal
And not the calm or the strife.

William Newell writes that...

there are those who are according to Spirit, who mind the Spirit's things: salvation, the person of Christ, the fellowship of the saints, the Word of God, prayer, praise prophecy, the blessed hope of Christ's coming, walking as He walked before men. True, many, many of these fall woefully short (as they well know); yet they mind the things of Spirit, the things of God, to some degree, while others will have nothing of them. (Romans 8: Expository Notes Verse by Verse)

Hendricksen sums up this section emphasizing that...

"Those who live according to the flesh allow their lives to be basically determined by their sinful human nature. They set their minds on—are most deeply interested in, constantly talk about, engage and glory in—the things pertaining to the flesh, that is, to sinful human nature. Those who live according to the Spirit, and therefore submit to the Spirit’s direction, concentrate their attention on, and specialize in, whatever is dear to the Spirit. In the conflict between God and sinful human nature the first group sides with human nature; the second sides with God. Paul is reminding the members of the church in Rome that it is impossible to be on both sides at once; that is, the basic—this adjective should be stressed!—disposition or direction of our lives is either on God’s side or on the side of sinful human nature. If a person persists in being worldly, he is on the side of the world and must expect the world’s doom. On the other hand, if the things concerning God and his kingdom are his chief concern, he can expect life: sweet communion with God, God’s love shed abroad in the heart, joy unspeakable and full of glory, all this and far more forever and ever." (Hendriksen, W., & Kistemaker, S. J. NT Commentary Set. Baker Book or Logos) (Bolding added)

John Piper addresses what the things of the Spirit look like in a believer's life...

The Spirit inspired the Word and therefore goes where the Word goes. The more of God’s Word you know and love, the more of God’s Spirit you will experience. Instead of drinking wine, we should drink the Spirit. How? By setting our minds on the things of the Spirit: “Those who live according to the Spirit set their minds on the things of the Spirit” (Ro 8:5). What are the things of the Spirit? When Paul said in 1 Corinthians 2:14, “The natural person does not accept the things of the Spirit,” he was referring to his own Spirit-inspired teachings (1Co 2:13). Therefore, above all, the teachings of Scripture are the “things of the Spirit.” We drink in the Spirit by setting our minds on the things of the Spirit, namely, the Word of God. And the fruit of the Spirit is joy (Gal 5:22). (Piper, J.. Desiring God. Page 148. Sisters, Or.: Multnomah Publishers)