
Verse 15 more or less repeats the same question he asked at the beginning of chapter 6, “What then? Shall we sin because we are not under the law but under grace?” Paul's answer is again an emphatic, 'By no means!'
In the second half of chapter 6 he chooses a fitting metaphor to make his argument - it is a metaphor that all of those in the church at Rome would have been instantly familiar with - the metaphor of slavery. Paul's point is that every human serves under one of two masters - we are either slaves to sin which leads to death or slaves to Christ which leads to life.
- We are all slaves to something
- The call to obedient slavery
- The reward promised to slaves in Christ