What shall we say then? Are we to continue in sin that grace may abound? 2 By no means! How can we who died to sin still live in it? – Romans 6:1-2
Paul proceeds carefully to disprove the propounded slander. He, however, first rejects it by an indignant negative, in order to impress it on the minds of his readers, that nothing can be more inconsistent than that the grace of Christ, the repairer of our righteousness, should nourish our vices.
Who have died to sin, &c. An argument derived from what is of an opposite character. “He who sins certainly lives to sin; we have died to sin through the grace of Christ; then it is false, that what abolishes sin gives vigour to it.” The state of the case is really this,—that the faithful are never reconciled to God without the gift of regeneration; nay, we are for this end justified,—that we may afterwards serve God in holiness of life. Christ indeed does not cleanse us by his blood, nor render God propitious to us by his expiation, in any other way than by making us partakers of his Spirit, who renews us to a holy life. It would then be a most strange inversion of the work of God were sin to gather strength on account of the grace which is offered to us in Christ; for medicine is not a feeder of the disease, which it destroys.
Commentary on the Epistle of Paul the Apostle to the Romans (Bellingham, WA: Logos Bible Software, 2010), 218–219.