Romans 6:15-23
15 What then? shall we sin, because we are not under the law, but under grace? God forbid.
16 Know ye not, that to whom ye yield yourselves servants to obey, his servants ye are to whom ye obey; whether of sin unto death, or of obedience unto righteousness?
17 But God be thanked, that ye were the servants of sin, but ye have obeyed from the heart that form of doctrine which was delivered you.
18 Being then made free from sin, ye became the servants of righteousness.
19 I speak after the manner of men because of the infirmity of your flesh: for as ye have yielded your members servants to uncleanness and to iniquity unto iniquity; even so now yield your members servants to righteousness unto holiness.
20 For when ye were the servants of sin, ye were free from righteousness.
21 What fruit had ye then in those things whereof ye are now ashamed? for the end of those things is death.
22 But now being made free from sin, and become servants to God, ye have your fruit unto holiness, and the end everlasting life.
23 For the wages of sin is death; but the gift of God is eternal life through Jesus Christ our Lord.
The Grace New Testament Commentary - Romans 6:17-23
6:17-18 Paul is grateful to God for the Christian experience of the Roman believers. In their unconverted days they had been slaves of sin, but after their conversion they had obeyed from the heart (i.e., sincerely) the form of teaching in which they had been instructed. That is to say, they had responded obediently to the Christian teaching they had received. Paul is no doubt thinking of the general format in which Christian instruction was usually given to converts to Christianity.
The Roman Christians were not total strangers to Paul (see Romans 16:1-20) and he even states that their "obedience" has become widely known (Romans 16:19). Since they had obeyed the Christian teaching in which they were instructed, their personal experience had been one of being liberated from sin and of being enslaved to righteousness. In other words, they had turned away from sin to do what was right in God's sight. Their servitude was now to Him and not to sin.
6:19 Paul is not altogether comfortable with describing their Christian obedience as being "enslaved to righteousness" (v 18). He does so due to the weakness of their flesh. A more abstract description would have failed due to their human limitations. Paul is working with an analogy, moving from the familiar (slavery to sin) to the unfamiliar (slavery to righteousness).
Formerly they had turned over their body's members as slaves to uncleanness and to wickedness. The result of this servitude to sinful practices was simply wickedness. The Roman Christians are now to turn over their body's members as slaves to righteousness. The result of this new form of active obedience will be the production of holiness. Thus the evil result of the former servitude can be replaced by the good result of a new servitude.
6:20-21 Paul expands his analogy between the old servitude and the new one. As slaves of sin they had been free from righteousness. Righteousness had been "powerless" in their lives. It had no control over what they did. It was not their "master." There could be no positive outcome from such a life. It was a life that now made them feel ashamed. The rhetorical question, So what fruit did you have then...? assumes that there was none at all. How could there be, since the result of those things could only be death?
In speaking of death here, Paul no doubt had physical death in mind, but his concept of death is much broader (cf. Romans 7:18-23; 8:6-13). For Paul, death is also an experience that is qualitatively distinct from true life. As Paul puts it in Eph 4:18, the unregenerate are "alienated from the life of God, because of the ignorance that is in them." But as he will show clearly in the following two chapters, such "alienation" from God's life is experienced also by the Christian when he submits to the desires of his spiritually-dead physical body.
6:22-23 Despite their unproductive past, the Roman Christians are now able to bear fruit that produces holiness. Their union with Christ has resulted in their being freed from sin and enslaved to God (cf. Romans 6:7). A new lifestyle is made possible in which the believer can "walk in newness of life" (Romans 6:4). This "newness of life" is eternal life. The believer's "walk" in this new life is the outcome of possessing that life in Christ. Thus the end result of producing holiness is nothing less than an experience of eternal life itself.
Paul can now wrap up the fundamental truths on which the entire unit (Romans 6:1-23) is based. On the one hand, death in all its aspects is the "pay-off" (wages) of sin. Obviously, a statement like this is deliberately broad enough to embrace all the various aspects in which death is the "compensation" for sin. In other words, it states a principle, and should not be narrowed to an exclusive reference to the "second death," or the lake of fire (Rev 20:14). Paul will later say to these believers that "if you live in relation to the flesh, you will die" (Rom 8:13) and that concept is one specific aspect of the principle he states here.
With sin, therefore, one receives what one has earned (wages). But eternal life is an unearned experience because at its core eternal life is the gift of God that is given in Christ Jesus our Lord. By virtue of our being in Christ (see Romans 6:3-4), we possess this gift. When we produce holiness, we are living out the gift that God gave us when we were justified by faith.
The word used here for gift (charisma) is picked up from Romans 5:15-16 where its occurrences are the first ones in the body of Paul's argument. As is clear from Romans 5:12-21, for Paul righteousness and life are part of one and the same gift (cf. Romans 5:17-18). The closing words of v 23, in Christ Jesus our Lord, are identical in Greek to the words that close v 11. Thus, they form an inclusio with v 11 and mark the present sub-unit (vv 12-23) as complete. The repeated words also serve to emphasize the truth that the eternal life which is given to us as a gift (by virtue of which we are "alive" [v 11]) is our possession in union with the Savior in whom we died and in whom we have been raised to walk in God's paths.