Romans 6:15
15What then? Shall we sin because we are not under law but under grace? May it never be!
The objection shifts from v. 1 (“shall we continue in sin that grace may abound?”) to a new misuse of v. 14: if we are not under law but under grace, may we sin? Paul again answers, “By no means!” Wesley on the verse just behind this question: under grace is the merciful dispensation of the gospel, which brings complete victory over sin to every one who is under the powerful influences of the Spirit of Christ. Grace is power, not license.
Wesleyan Arminians see a free refusal, not a paper one. Being under grace frees from sin’s dominion so that we may present ourselves as slaves to righteousness. It does not make sin safe, and it does not make yielding to the old master impossible or harmless. The holy no is the start of a commanded life, not the announcement that the regenerate cannot return.
Calvin: the wisdom of the flesh thinks that when the law is removed all discipline falls to the ground, and no distinction remains between good and evil. We are much deceived if we think the righteousness God approves in his law is abolished when the law is abrogated; nothing is taken away but the curse, to which all men without grace are subject. By no means! because Christ sanctions the right way of living; he does not abrogate it.
Those under grace are not under the law’s condemning yoke, yet they are not without a master. Grace includes both remission and the Spirit who forms us anew unto good works. The objection assumes law is the only restraint; Paul will show that a new slavery—to righteousness—has already begun in the faithful.