AND THAT NO MAN TRANSGRESS AND DEFRAUD HIS BROTHER IN THE MATTER: to me huperbainein (PAN) kai pleonektein (PAN) en to pragmati ton adelphon autou: (Ex 20:15,17; Lev 19:11,13; Deut 24:7; 25:13-16; Proverbs 11:1; 16:11; 20:14; Proverbs 20:23; 28:24; Isaiah 5:7; 59:4-7; Jeremiah 9:4; Ezekiel 22:13; 45:9-14; Amos 8:5,6; Zephaniah 3:5; Malachi 3:5; Mark 10:19; 1 Corinthians 6:7-9; Ephesians 4:28; James 5:4) (Leviticus 25:14,17; 1 Samuel 12:3,4; Proverbs 22:22; Jeremiah 7:6; Micah 2:2; Zephaniah 3:1; James 2:6)

In this matter, then, no man should do wrong to his fellow-Christian or take advantage of him. We have told you this before, and we strongly warned you that the Lord will punish those who do that. (GNT)

not to take advantage of or exploit a brother in this matter, for the Lord is an avenger in all these things, as we told you before and solemnly affirmed. (NAB)

In this matter no one should violate the rights of his brother or take advantage of him, because the Lord is the avenger in all these cases, as we also told you earlier and warned you solemnly. (NET)

He wants nobody at all ever to sin by taking advantage of a brother in these matters; the Lord always pays back sins of that sort, as we told you before emphatically. (NJB)

And this also is God’s will: that you never cheat in this matter by taking another man’s wife because the Lord will punish you terribly for this, as we have solemnly told you before. (TLB)

No man transgress or defraud his brother - Some commentaries favor this as a reference to a Christian brother but others feel Paul is speaking of men and women in general. Certainly the charge to never take advantage of another person in the area of sexuality has a broad application, for sex in any form outside of marriage is off limits.

Transgress (5233)(huperbaino from hupér = beyond + baíno = to go) means literally  to step over or go beyond. The idea is to step over a boundary, to break over a barrier, to go beyond prescribed limits, to exceed the proper limits,  go over the line, go beyond the bounds, go pass the law. Clearly the idea is to go to far. Figuratively, as used here in the only NT use, huperbaino means to overstep certain limits and so to to transgress or sin against. The idea is don't sin against another person by stepping over the line and exceeding the lawful limits. The English word transgress is means to  go beyond the limits set by  moral principles, standards, laws, etc.

Darby translates

not overstepping the rights of and wronging the brother.

Hiebert comments that the verbal form of huperbaino...

literally means "to go beyond" and carries the thought of passing over the line that divides right from wrong. The present tense with the negative (me) has the force "that there be no going beyond." (Hiebert, D. Edmond: 1 & 2 Thessalonians: BMH Book. 1996)

Huperbaino is used 10 times in the Septuagint (LXX) and most of these uses are with the literal meaning (1Sa 5:5; 2Sa 18:23; 22:30; Job 9:11; 14:5; 24:2; 38:11; Ps 18:29; Pr 9:18; Jer. 5:22; Micah 7:18) as for example in...

2 Samuel 18:23 "But whatever happens," he said, "I will run." So he said to him, "Run." Then Ahimaaz ran by way of the plain and passed up (Lxx = huperbaino = outrun)  the Cushite.

2 Samuel 22:30 (Ps 18:29)  "For by Thee I can run upon a troop; By my God I can leap over  (Lxx = huperbaino) a wall.

Micah 7:18 Who is a God like Thee, who pardons iniquity And passes over (Lxx = huperbaino) the rebellious act of the remnant of His possession? He does not retain His anger forever, Because He delights in unchanging love.

Vincent writes that huperbaino is found...

Often in LXX, mostly in the literal sense of overpassing limits. Also of overtaking, passing by, surpassing, as in wickedness or cruelty. It is an expansion of the preceding thought. Pursue your business as holy men: do not overreach or defraud. It is the overstepping of the line between mine and thine. It is used absolutely, being defined by the succeeding clause. The A V is literal, go beyond. Rev. renders transgress. Weizsäcker and Bornemann “ubergreife overreach.” So Rev. margin. This last is the best.

That no man...defraud - Defraud means to selfishly, greedily take something for personal gain and pleasure at someone else’s expense. Webster says that to defraud is to get something by dishonesty or deception and stresses depriving one of his or her rights and usually connotes a deliberate perversion of the truth. Defraud means  to take away or withhold money, rights, property, etc., from a person by fraud (intentional perversion of truth in order to induce another to part with something of value). That is a good picture of what happens in illicit sex for the perpetrator is taking something away from the other person! As with transgress, defraud includes the idea of taking advantage of someone, here in the are of sexual sin. Whenever believers seek to satisfy their physical desires and obtain sexual pleasure at the expense of another individual, they have violated this command.

Defraud (4122) (pleonekteo  from pleíon = more + écho = have <> pleonektes degrees one who wants more, person covetous of something that others have, a defrauder for gain) literally means to have more than another and then to take advantage of any one. To claim more. To covet. To have more than one's due. To selfishly attempt to gain more at all costs and by all means disregarding others and their rights. Defraud means to selfishly and greedily take something at someone else's expense.

Hiebert adds that pleonekteo...

does not indicate the nature of the wrong being done, but the idea of selfish and self-seeking fraud is involved in the term. The present tense prohibits the continuation of such a practice. (Hiebert, D. Edmond: 1 & 2 Thessalonians: BMH Book. 1996)

Don't go beyond the line that God has drawn and take advantage of another person in the matter of sexual sin.

See discussion of the related word pleonexia which describes a strong desire to acquire more and more material possessions, especially that which is forbidden. This desire to have more  is irrespective of one's need and thus describes an insatiable selfishness. Greed is what you desire and what you desire more of becomes your ''god'' and you end up serving that ''god.'' The individual whose life is dominated by the desire to get things has set up things in the place of God and that is the essence of idolatry.

Greeks defined pleonekteo as “the spirit which is always reaching after more and grabbing that to which it has no right.” It is aggressive getting. It is not the miser’s spirit, for it aimed to get in order to spend, so that it could live in more luxury and greater pleasure; and it cared not over whom it took advantage so long as it could get. ) means to take advantage of someone, usually as the result of a motivation of greed, to exploit, exploitation.

What does that word defraud mean? It stresses depriving one of his or her rights and usually connotes deliberate perversion of the truth. Defraud means to selfishly, greedily take something for personal gain and pleasure at someone else’s expense. It means to take advantage of someone for personal gain, personal pleasure.

When someone desires their sexual pleasure, they take advantage of someone else to get it. 

There are only 5 uses of pleonekteo in the NT...

2 Corinthians 2:11 in order that no advantage be taken of us by Satan; for we are not ignorant of his schemes. (Vincent writes that literally pleonekteo is "in order that we be not made gain of, or overreached, by Satan. Rev., that no advantage may be gained over us.)

2 Corinthians 7:2 Make room for us in your hearts; we wronged no one, we corrupted no one, we took advantage of no one.

2 Corinthians 12:17 Certainly I have not taken advantage of you through any of those whom I have sent to you, have I? 18 I urged Titus to go, and sent the brother with him. Titus did not take any advantage of you, did he? Did we not conduct ourselves in the same spirit and walk in the same steps?

1Thessalonians 4:6 and that no man transgress and defraud his brother in the matter because the Lord is the avenger in all these things, just as we also told you before and solemnly warned you.

John Piper comments that...

When we sin sexually we are not seeking the highest good of others, neither the woman or the man we sin with, nor the person we fantasize about nor the person in the pornography, nor the spouse or parent of any of these. It is not Christian love that moves us in any of this. It is simply selfish desire. But Christians are people deeply moved by love for others. Christians love people; they don’t use them. (1Thessalonians 4:1-8)

Morris writes that...

Adultery is an obvious violation of the rights of another. But promiscuity before marriage represents the robbing of the other that virginity which ought to be brought to a marriage. The future partner of such a one has been defrauded.

Guzik observes that...

Repeatedly in Leviticus 18 - a chapter where God instructed Israel on the matter of sexual morality - the idea is given that one may not uncover the nakedness of another not their spouse. The idea is that the nakedness of an individual belongs to their spouse and no one else, and it is a violation of God’s law to give that nakedness to anyone else, or for anyone else to take it. (David Guzik. The Enduring Word Commentary Series)

Keener writes that...

Adultery, or “wife stealing,” as it was often considered, was punishable by banishment under Roman law; in some circumstances, a couple caught in the act could be killed on the spot. Adultery seems to have been common and usually unpunished, however; but a husband who learned that his wife was committing adultery was required by law to divorce her or himself be prosecuted on the charge of lenocinium—“pimping.” Palestinian Judaism could no longer execute the Old Testament death penalty for adultery, but Jewish people believed that what they could not execute, God would (especially on the day of judgment). (Keener, Craig: The IVP Bible Background Commentary: New Testament. 1994. IVP)

Brethren (80) (adelphos from collative a = denoting unity + delphús = womb) is literally one born from same womb and so a male having the same father and mother as reference person.

Figuratively, adelphos is usually used by Paul to refer to fellow believers in Christ who are united by lineage of being in Christ and in the family of God Who is now their Father. It is possible however that in this present usage Paul is broadening the term to include non-believers, an interpretation favored by Vine who writes that...

though there is no other instance in Paul’s epistles of the use of this word of mankind in general, it is difficult to suppose that the apostle here limited its meaning to the Christian relationship; cp. Matthew 7:3 (see note). (Vine, W. Collected writings of W. E. Vine. Nashville: Thomas Nelson or Logos)

Lightfoot supports this broader interpretation of brothers writing that

this is a duty which extends to the universal brotherhood of mankind, and has no reference to the special privileges of the close brotherhood of the Gospel.

Keathley comments that ...

the brother in this verse as most likely another person, not necessarily another Christian male. “This seems clear from the fact that this person is a victim of illicit sex. Sexual immorality wrongs the partner in the forbidden act by involving him or her in behavior contrary to God’s will and therefore under His judgment.” Ryrie agrees though he acknowledges this is not the Apostle’s normal use of “brother.” He writes, “Paul uses “brother” here not in the restricted sense of a brother in Christ but in the general sense of a brother man. There is no other instance in Paul’s writings of this use of brother.” Paul’s point is that just as stealing is a sin against one’s neighbor, so sexual immorality is a transgression against others. (1Thessalonians 4:1-12)

F F Bruce interprets brother as...

meaning probably a fellow Christian (although the action would be equally reprobated if the victim of the “trespass” were a pagan). (Bruce, F F: 1 and 2 Thessalonians. Word Biblical Commentary. Dallas: Word, Incorporated. 1982 or Logos)

The matter  (4229) (pragma from prásso = to do, perform = suffix –ma = the result of; English = pragmatic [dealing with things in a way that is based on practical rather than theoretical considerations: practical as opposed to idealistic]; derivative words = pragmateia = affairs in 2 Timothy 2:4 [note], pragmateuomai = trade, do business, put capital to work, Lu 19:13) describes that which has been done or that which happens (a happening), and thus a deed, a thing, an event, an occurrence or an accomplished fact. In this meaning pragma speaks of something in the past. When speaking of something in the present or future, pragma means that which occurs as a result of activity -- the thing being done or to be done (in secular Greek in the phrase "great undertakings", "the tasks of everyday life"), matter, business, affair.

In this matter - Means in the sphere of the conduct prohibited where the definite article (modifying "matter") makes it specific, pointing to the matter under discussion, and therefore should not be translated generally, "in any matter" as does the KJV. Some argue that the matter could have one of two distinct interpretations -- sexual impurity and dishonesty in business.

Milligan asserts that

the words are too closely connected with what precedes and what follows (1Thes 4:7, 'uncleanness') to admit of any such transition to a wholly new subject.

Moffatt concludes that

Paul is still dealing with the immoralities of men, but now as a form of social dishonesty and fraud. The metaphors are drawn from trade, perhaps as appropriate to a trading community.

In the present context, which remains unchanged throughout v1-8, demands that this refer to all the destructive social and spiritual implications of illegitimate sexual activity. Solomon who ironically failed to follow his own advice wrote the following wisdom and warning regarding sexual dalliances...

Proverbs 6:20 My son, keep the laws of thy father, and reject not the ordinances of thy mother: 21 Bind them continually on your heart; Tie them around your neck. 22 When you walk about, they will guide you; When you sleep, they will watch over you; and when you awake, they will talk to you. 25 For the commandment is a lamp, and the teaching is light; and reproofs for discipline are the way of life, 24 (Observe carefully from the prior passages what serves to protect one from sexual indiscretion) To keep you from the evil woman (Septuagint or LXX  = "married woman") , from the smooth tongue (LXX  = diabole = slander, false accusations - cp word for devil = diabolos from dia = between + ballo = cast - the idea is cast between, e.g., a husband and a wife and so divide them which is what adultery does!) of the adulteress (LXX = "strange woman" literally "a woman belonging to another").

Proverbs 6:25 Do not desire her beauty in your heart (not just in your eyes but in your heart, cp Jesus' warning in Matthew 5:27 [notes]; 28; 29) (LXX translation = "do not let your strong desire or lust [epithumia] for her beauty overcome [nikao] or conquer you"), nor let her catch (Hebrew = laqah = lay hold of, seize, snatch. LXX = sunarpazo from sun = with speaks of an intimate association + harpazo = seize - means to seize suddenly and violently! Note the passive voice = be seized by a force from without! Sunarpazo was used in Acts 27:15 of a ship caught in a storm and being swept off course by a tempestuous wind ~ think of an the effects of an adulteress!) you with her eyelids (cp Job's solution for this danger = Job 31:1) 26 (LXX = "the value of a harlot"; ESV "the price of a prostitute is only a loaf of bread") For on account of a harlot one is reduced to a loaf of bread (reduced to poverty ~ crust of bread), and an adulteress (Hebrew = a man's wife = a married woman) hunts (Lxx = agreuo = is a term used for hunting or fishing and conveys idea of catching one unaware and taking advantage of the man in an unguarded moment! Guard your heart continually. Pr 4:23) for the precious life (cp the trap David fell into because he did not make a covenant with his eyes and was trapped in this unguarded moment! see 2Sa 11:2) 27 Can a man take fire in his bosom (see Job's comment - Job 31:12), and his clothes not be burned? 28 Or can a man walk on hot coals, and his feet not be scorched?

Proverbs 6:29 So is the one who goes in to his neighbor's wife. Whoever touches (Lxx =  hapto means to fasten or cling to, to make close contact, to kindle or set on fire! What a vivid picture of the powerful effect of touch! You can't look and likewise you better not touch! In Greek the idiom "touch a woman" actually means to have intercourse with her. See hapto in Ge 20:6) her will not go unpunished. 30 Men do not despise a thief if he steals To satisfy himself when he is hungry; 31 But when he is found, he must repay sevenfold; He must give all the substance of his house. 32 The one who commits adultery with a woman is lacking sense; He who would destroy himself does it (Lxx = "procures destruction to his soul"!). 33 Wounds and disgrace he will find, and his reproach will not be blotted out. 34 For jealousy enrages a man, and he will not spare in the day of vengeance. 35 He will not accept any ransom, nor will he be content though you give many gifts. (Proverbs 6:20-35)

The delicacy of Paul makes him refrain from plainer terms and the context makes it clear enough as in 2Cor 7:11. Note Greek uses definite article so it is "the specific matter of business" which in context is illicit sexual activity.

Sexual immorality defrauds more than just one party for it is a sin against God’s Holy Spirit (1Co 6:19), a sin against one’s own body (1Cor 6:18) and is also a sin against other persons. Joseph recognized this principle when tempted by Potiphar's wife declaring to her

There is no one greater in this house than I, and he has withheld nothing from me except you, because you are his wife. How then could I do this great evil, and sin against God?" (Ge 39:9)

Barnes comments that the matter  means...

to the reading in the margin, this would refer to the particular matter under discussion 1Th 4:3-5 to wit, concupiscence (strong desire, especially sexual desire), and the meaning then would be, that no one should be guilty of illicit intercourse with the wife of another (Ed comment: assuming "vessel in verse 4 referred only to one's wife). --as Hammond, Whitby, Macknight, Rosenmuller, suppose that this is a prohibition of adultery, and there can be no doubt that it does include this. But there is no reason why it should be confined to it. The Greek is so general that it may prohibit all kinds of fraud, overreaching, or covetousness, and may refer to any attempts to deprive another of his rights, whether it be the right which he has in his property, or his rights as a husband, or his rights in any other respect. It is a general command not to defraud; in way to take advantage of another; in no way to deprive him of his rights (Ed comment: but the context speaks especially of defrauding in the area of sexual activity of any kind outside of marriage).  (Albert Barnes. Barnes NT Commentary)

In the previous two verses Paul’s appeal was based on the importance of sexual purity for the sake of the Christian himself. In this verse Paul appealed on the basis of the other person involved in the immoral act. The brother as noted earlier could refer to any other human, not necessarily a Christian. Sexual immorality wrongs the partner in the forbidden act by involving him or her in behavior contrary to God’s will and therefore under His judgment. Two or more people practicing sex out of God’s will are calling God’s wrath down on themselves (Heb 13:4). The initiator of the act takes advantage of his partner in sin by fanning the fire of passion till self-control is lost.

Sexual sin disregards God, ignoring His holiness, spurning His will, defying His commands, rejecting His love, flaunting His grace and mercy and in short is disobedient and selfish. And as Hiebert notes "Any illegitimate sexual relationship has in it the potential for social complications that cannot be calculated in advance."

BECAUSE THE LORD IS THE AVENGER IN ALL THESE THINGS: dioti ekdikos o kurios peri panton touton kathos: (Deuteronomy 32:35; Job 31:13,14; Psalms 94:1; 140:12; Proverbs 22:22,23; Ecclesiastes 5:8; Isaiah 1:23,24; Romans 1:18; 12:19; Ephesians 5:6; 2 Thessalonians 1:8)

Because  (1360) (dioti from diá = for + hóti = that) means on account of this or that, for this reason, that, simply because, for. Here Paul passes from the behavior called for in order to be sexually pure to the reason or motives for striving to be sexually pure.

Given the loose morals and sexual laxity throughout the ancient world in the first century, the readers might have been wondering "Why is this so important? After all, everybody's behaving this way, so why shouldn't we?" This sounds very modern doesn't it? -- Situation ethics. Relative values. Well, Paul anticipates such a question and proceeds to give 4 reasons we should strive to cultivate sexual purity:

(1) the Lord is the Avenger - God satisfies justice by inflicting the due punishment upon the wrongdoer. This reason appeals to the fear of the consequences of disobedience.

(2) God has not called us to impurity

(3) God has called us in sanctification (holiness)

(4) If we reject this warning we are rejecting God!

Avenger  (1558) (ekdikos from ek = from, out + díke = justice) literally refers to one outside of that which is lawful. One who carries out what is right. It refers to one who exacts a penalty from a person, an avenger, a punisher. The ekdikos is the one who exacts satisfaction for a wrong by punishing the wrongdoer or by inflicting punishment in retaliation for an injury or offense. In secular Greek ekdikos was used for the office of an official legal representative.

The only other Biblical use of ekdikos is in Romans...

for it (authority) is a minister of God to you for good. But if you do what is evil, be afraid; for it does not bear the sword for nothing; for it is a minister of God, an avenger who brings wrath upon the one who practices evil. (see note Romans 13:4)

In this section Paul shoots his rifle over their heads as if to say, brothers I'm not kidding, this is serious business.

Marshall notes that...

It is not popular with some people who argue that if God commands Christians to return good for evil and love to their enemies, he himself ought to follow the same principles. The difficulty is probably that in contemporary English the words `avenge' and 'vengeance' have taken on the sense of acting out of personal vindictiveness, whereas in the Bible the thought is rather that God takes the side of the victims of crime and wickedness and secures justice for them, and that he acts as the upholder of the moral order against those who think that they can break it with impunity. (I. Howard Marshall. 1 and 2 Thessalonians. The New Century Bible Commentary).

Hiebert observes that in appealing to God as avenger Paul is bringing to mind the consequences which should stimulate a godly fear, whereas he

might have appealed to the bitter physical, psychological, and social consequences of immorality. His emphasis rather is eschatological, the coming judgment day. A just God and a coming day of judgment are factors that cannot be left out of consideration when dealing with moral practices.

The Lord is the Avenger as Paul wrote in Romans...

Never take your own revenge, beloved, but leave room for the wrath of God, for it is written, "VENGEANCE IS MINE, I WILL REPAY," says the Lord. (see note Romans 12:19)

The writer of Hebrews says...

Let marriage be held in honor among all, and let the marriage bed be undefiled; for fornicators and adulterers God will judge. (see note Hebrews 13:4)

Jehovah says in Deuteronomy that taking vengeance is a prerogative that He retains for Himself declaring...

'Vengeance is Mine, and retribution, In due time their foot will slip; For the day of their calamity is near, And the impending things are hastening upon them.' (Deuteronomy 32:35)

Job asked...

"If I have despised the claim of my male or female slaves When they filed a complaint against me, What then could I do when God arises, And when He calls me to account, what will I answer Him? (Job 31:13,14)

David understood that the Lord is the Avenger...

I know that the LORD will maintain the cause of the afflicted, And justice for the poor. (Comment:

David's sin of sexual immorality (adultery cp Lev 18:20, Deut 22:22, Pr 6:32, 1Cor 6:9, Hebrews 13:4) with Bathsheba and murder of Uriah reaped the vengeance of the Jehovah (cp Lev 20:10, 24:17). Meditate on the wages of sin in David's life in  2Samuel 12, especially the following passages...

'Why have you despised the word of the LORD (cp Nu 15:31) by doing evil in His sight (cp 1Sa 15:19)? You have struck down Uriah the Hittite with the sword (2Sa 11:15,17), have taken his wife to be your wife (2Sa 11:27), and have killed him with the sword of the sons of Ammon.
10 'Now therefore, the sword shall never depart from your house, because you have despised Me and have taken the wife of Uriah the Hittite to be your wife.'
11 "Thus says the LORD, 'Behold, I will raise up evil against you from your own household; I will even take your wives before your eyes, and give them to your companion, and he shall lie with your wives in broad daylight.
12 'Indeed you did it secretly, but I will do this thing before all Israel, and under the sun. (see retribution wrought by Absalom 2Sa 16:21-22)'"
13 Then David said to Nathan , "I have sinned against the LORD." (cp 1Sa 15:24, 2Sa 24:10, Ps 32:5, 51:4) And Nathan said to David, "The LORD also has taken away your sin (Ps 32:1, 103:9, 12, Isa 38:17, 43:25, Micah 7:18-19, Zech 3:4); you shall not die. (2Samuel 12:9-13)

Keathley notes that ...

Sexual sin will not go unpunished. It has its immediate consequences in the personal discipline of God on the believer who transgresses and on a society which ignores the laws of God. The tremendous effect of this can be seen on the home and in the transmission of sexually-transmitted diseases so prevalent in our world today. But there is also the future aspect of loss of rewards (see 2Cor 5:9-10) for those believers who ignore God’s truth. (1Thessalonians 4:1-12)

John Piper spares no words in warning...

that the consequences of lust are going to be worse than the consequences of nuclear war. All that nuclear war can do is kill the body. And Jesus said, "Do not fear those who kill the body and after that have no more that they can do. But I will warn you whom to fear. Fear him who after he has killed has power to cast into hell" (Luke 12:4-5). In other word's God's vengeance is much more fearful than earthly annihilation. And according to 1 Thessalonians 4:6 God's vengeance is coming upon those who disregard the warning against lust.

(He adds) So I have learned again and again from first hand experience that there are many professing Christians who have a view of salvation that disconnects it from real life, and that nullifies the warnings of the Bible and puts the sinning person who claims to be a Christian beyond the reach of Biblical threats. And this doctrine is comforting thousands on the way to hell.

Jesus said, if you don't fight lust, you won't go to heaven.

The stakes are much higher than whether the world is blown up by a thousand bombs. If you don't fight lust, your won't go to heaven (see notes 1 Peter 2:11, Colossians 3:6; Gal. 5:21; 1 Cor. 6:10; Hebrews 12:14).

Are we not then saved by faith—by believing in Jesus Christ? We are indeed! Those who persevere in Faith shall be saved (Matthew 24:13; 10:22; 1 Cor. 15:3; Col. 1:23; 2 Thess. 2:13). How do you lay hold on eternal life? Paul gives the answer in 1 Ti 6:12—"Fight the good fight of faith: lay hold on eternal life."

That leads us to our main concern this morning—to show that the fight against lust is a battle against unbelief. And the fight for sexual purity is the fight of faith.

The great error that I am trying to explode in these messages is the error that says, faith in God is one thing and the fight for holiness is another thing. Faith gets you to heaven and holiness gets you rewards. You get your justification by faith, and you get your sanctification by works. You start the Christian life in the power of the Spirit, you press on in the efforts of the flesh. This is the great evangelical error of our day. The battle for obedience is optional, they say, because only faith is necessary for salvation.

Our response: the battle for obedience is absolutely necessary for salvation because it IS the fight of faith. The battle against lust is absolutely necessary for salvation because it is the battle against unbelief. Faith alone delivers from hell and the faith that delivers from hell delivers from lust.

I hope you can see that this is a greater gospel than the other one. It's the gospel of God's victory over sin, not just his tolerance of sin. It is the gospel of Romans 6:14 "Sin will have no dominion over you, since you are not under law but under grace." Almighty grace! Sovereign grace!

He breaks the power of cancelled sin,
He sets the prisoner free;
His blood can make the foulest clean,
His blood availed for me.
(Play O for a Thousand Tongues to Sing)

Blessed are the pure in heart, for they shall see God (see note Matthew 5:8). This is God's demand and this is God's gift. It is all of grace. That's why the only fight we fight is the fight of faith—the fight to rest so fully in the grace of God—to be so satisfied with the glory of God—that temptation to sin loses its power over us. (1Thessalonians 4:1-8: Battling Unbelief of Lust)

Though these offenses are not generally punished in criminal courts today, the Lord is the Avenger of all such ultimately dealing out just recompense for such sins (cf. see notes Colossians 3:4;  3:5; 3:6; 3:7; Hebrews 13:4). Regular term in the papyri for legal avenger. Modern men and women need to remember that God is the avenger for sexual wrongs both in this life and the next.

God is no respecter of persons. He must deal with His children when they sin (see notes Colossians 3:23; 3:24; 3:25). A church member criticized her pastor because he was preaching against sin in the lives of Christians.

“After all,” she said, “sin in the life of a believer is different from sin in the lives of unsaved people.”

“Yes,” replied the pastor, “it is worse.”

How will God avenge sexual sin? It could be in an unfulfilling sexual life and marriage. It could be by bringing about a miserable marriage or even allowing a divorce. It could be in temporal chastening or discipline,  through a sexually transmitted disease (STD). He could avenge by bringing about negative circumstances, an absence of blessing, a plethora of trials and trouble or even death. Sexual sin could and most likely will result in the loss of eternal rewards in some measure. This section of Scripture is a solemn warning indeed, given the torrid temptations in our sex sickened society and the prevalence of illicit sexual activity in the evangelical community!

While it is true that the Christian is not under condemnation (note Romans 8:1), it is also true that he is not free from the harvest of sorrow that comes when we sow to the flesh as Paul made clear to the believers in Galatia writing...

Do not be deceived (present imperative - stop being deceived), God is not mocked; for whatever a man sows, this he will also reap. For the one who sows to his own flesh shall from the flesh reap corruption, but the one who sows to the Spirit shall from the Spirit reap eternal life. (Galatians 6:7,8)

When King David committed adultery, he tried to cover his sin, but God chastened him severely. Read Psalm 32 and Psalm 51 to see what he lost during the time of chastening. When David confessed his sins, God forgave him; but God did not change the consequences. David reaped what he had sown, and it was a painful experience for him and his family.