OR DO YOU NOT KNOW, BRETHREN: he agnoeite (2PPAI) adelphoi:

Wayne Barber introduces this section writing ...

Regarding the little word "or" Newell writes that...

The King James, by its failure to translate the chapter’s opening word “Or,” (KJV "7:1 Don't you realize, brothers and sisters") to which God gives the emphatic position in this argument, obscures the whole meaning of the passage and context. Unless we connect Chapter 7:1 with Chapter 6:14, (as the proper translation “or” does), we cannot properly understand the passage. (Romans 7)

Do you not know (50) (agnoeo from a = not + noéo = perceive, understand) not have information about, to not know, to be unaware of, to be ignorant of, ignorance. "Know" is a key word in Ro 6 (see exposition of Romans 6:3)

Someone has quipped that when Paul begins a sentence with "do you not know" (or "are ye ignorant") concerning the saints, it often turns out that they are ignorant!

William Newell observes in Romans 7...

"we have a chapter of two sections, (1) verses I through 6 and (2) verses 7 through 25: both of which we are prone to misunderstand and misapply, unless we exercise much prayerful care...The King James, by its failure to translate the chapter's opening word "Or, " to which God gives the emphatic position in this argument, obscures the whole meaning of the passage and context. Unless we connect Chapter 7.1 with Chapter 6.14, (as the proper translation "or" does), we cannot properly understand the passage." (Romans 7)

FOR I AM SPEAKING TO THOSE WHO KNOW THE LAW: ginoskousin (PAPMPD) gar nomon lalo (1SPAI): (Ro 2:17-18; Ezra 7:25; Pr 6:23; 1Cor 9:8; Gal4:21) (Ro 7:6; 6:14)

He speaks to those who have a knowledge of a general principle of ALL law (definite article not before "nomon" so not just "The Law" of Moses for example although it certainly would include that source.) It is quite possible that Paul is not interested so much in identifying the law he has in mind as in pointing to its character as law, that which has binding force, which is the fundamental character of any law or regulation.
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THAT THE LAW HAS JURISDICTION OVER  A PERSON AS LONG AS HE LIVES: hoti o nomos kurieuei (3SPAI) tou anthropou eph oson chronon ze:

Jurisdiction (2961) (kurieuo from kurios = master - power of control rather than physical strength) means to have dominion over, to be lord of, to exercise lordship over. In Scripture kurieuo personifies various things which control human life such as Law, Sin, Death, emphasizing that each of these entities has dominion over or exerts mastery over fallen mankind. Here clearly Paul personifies the Law as that which controls human life. 

Already in this initial statement we have a clue for determining the thought that Paul is about to develop. The law has authority over a person only for his lifetime. Since it has been established that the believer died with Christ, one can anticipate the conclusion--that whatever authority the law continues to exercise over others, for the believer that power has been abrogated.

Ironside comments that Paul's

argument here is that the law has dominion over men until death ends its authority or ends their relationship to it. But he has just been showing us in the clearest possible way that we have died with Christ; therefore we died not only to sin, but we have died to the law as a rule of life. Is this then to leave us lawless? Not at all: for we are now, as he shows elsewhere (1Cor 9:21 ), "under the law to Christ", or "enlawed" - that is, legitimately subject - to Christ our new Head. He is husband as well as Head, even as Ephesians 5 so clearly shows. (Romans Commentary)

Though freed from the LAW with its stern demands--
No longer ruled by its harsh commands--
I'm bound by Christ's love and am truly free
To live and to act responsibly - D J De Haan

Romans 7 depicts the law as actually awakening rebellious desires within (see note Romans 7:5). Being told not to do something excites our old man, our flesh to desire to express itself. By daily walking and talking with Christ, we can go from ''NO'' power in the law to ALL power in Christ. Remember that walking is simply placing one foot before another and then repeating the process. That is how believers can learn to walk in the Spirit of Christ and in His power. In Christ, God's love was expressed and His law was satisfied (Gal 3:13) and our call now is to work out our salvation in Christ with fear and trembling (see note Philippians 2:12)

FOR THE MARRIED WOMAN IS BOUND BY LAW TO HER HUSBAND WHILE HE IS LIVING: e gar hupandros gune to zonti (PAPMSD) andri dedetai (3SRPI) nomo: (Ge 2:23,24; Nu 30:7,8; 1Cor 7:4,39)

Married (5220) (hupandros from hupo = under + aner = a husband) literally means "under (subject to) a husband" which is God's ordained design to assure proper order. But these husbands are to love their wives enough to die for them (see note Ephesians 5:25) so this does not make the wife a "doormat"! So if you are telling your wife "Woman you need to submit" then you need to understand submission in the whole context of scripture and not use isolated passages out of context which results in a pretext and an improper application. (See related topic: word study on hupotasso: be subject to or submit to)

Woman (1135) (gune) can mean wife or woman.

Bound (1210) (deo) means literally to tie objects together tie up. In this context the use is figurative and means to cause someone to be under authority of someone or something else, to restrict, to place under (the jurisdiction of). It means to put under obligation. Deo is in the perfect tense meaning that she “has been bound and remains bound " The perfect tense pictures "permanence" until he dies.

Lives (2198) (zao) (Click noun form zoe) means to be alive physically and refers to existence as opposed to death or nonexistence. Figuratively zao means to enjoy real life or to have true life, as  God meant it to be lived, although that is not the primary meaning in this context.

BUT IF HER HUSBAND DIES SHE IS RELEASED FROM THE LAW CONCERNING THE HUSBAND: ean de apothane (3SAAS) o aner katergetai (3SRPI) apo tou nomou tou andros:

"If" = Subjunctive used in 3rd-class condition = this condition is a real possibility.

Newell remarks that...

Here Paul uses the fundamental law of domestic relationship to illustrate the fact that only death breaks a legal bond. This is the evident, simple meaning in this passage. This husband-and-wife illustration is marvelously chosen. It is of world-wide application—instantly understood everywhere; and it sets forth perfectly what the apostle desired—that is, to describe the dissolution of a relationship by death, thus making possible a new relationship. (Romans 7)

We have died (599) (apothnesko from apo = marker of dissociation implying a rupture from a former association,  separation, departure, cessation + thnesko = die) literally means to die off and can speak of physical (as here) or literal death.

Released (2673) (katargeo from kata = intensifies meaning + argeo = be idle) means to make the power or force of something ineffective. It means to render powerless. To reduce to inactivity.  Do away with. To put out of use. The basic idea of katargeo is to cause something to be idle or useless,  inoperative or ineffective and in this verse is translated "released".

Katargeo is in the perfect tense which means that the wife has been released and continues in this state of release, thus speaking of the fact that she is permanently released. She is bound to him by marriage as her husband while he lives, and obviously his death frees her from that marriage.

SO THEN IF, WHILE HER HUSBAND IS LIVING: ara oun zontos (PAPMSG) tou andros: (Ex 20:14; Lev 20:10; Nu 5:13-31; Dt 22:22-24; Mt 5:32; Mk 10:6-12; John 8:3-5)

So then (686) (ara) is an inference drawn from that which precedes and means so, therefore, then, now, consequently. Ara marks transition to what naturally follows from the preceding.

Alive (2198) (zao) (