John Calvin Commentary Romans 6:17

"But thanks be to God, that, whereas ye were servants of sin, ye became obedient from the heart to that form of teaching whereunto ye were delivered;" — Romans 6:17 (ASV)

But thanks be to God, etc. This is an application of the analogy to the present subject. Although they were only to be reminded that they were not now the servants of sin, Paul still adds a thanksgiving. He does this, first, so that he might teach them that this was not through their own merit but through the special mercy of God; and secondly, so that by this thanksgiving, they might learn how great was the kindness of God, and that they might thereby be more motivated to hate sin. And he gives thanks, not for that time during which they were the servants of sin, but for the liberation that followed, when they ceased to be what they were before. But this implied comparison between their former and present state is very emphatic, for the Apostle addresses the slanderers of the grace of Christ when he shows that without grace the entire human race is held captive under the dominion of sin, but that the kingdom of sin comes to an end as soon as grace manifests its power.

From this we learn that we are not freed from the bondage of the law so that we may sin; for the law does not lose its dominion until the grace of God restores us to Him, to renew us in righteousness. Therefore, it is impossible for us to be subject to sin when the grace of God reigns in us, for as we have stated before, the term 'grace' includes the spirit of regeneration.

You have obeyed from the heart, etc. Here, Paul compares the hidden power of the Spirit with the external letter of the law, as if he had said, “Christ inwardly forms our souls in a better way than when the law constrains them by threatening and terrifying us.” Thus, the following slander is dispelled: “If Christ frees us from subjection to the law, He brings liberty to sin.” Indeed, He does not allow His people unbridled freedom, so that they might frisk about without any restraint, like horses let loose in the fields; but He brings them to an ordered way of life.

— Though Erasmus, following the old version, has chosen to translate it the “form” (formam) of doctrine, I have felt constrained to retain type, the word which Paul uses; some may perhaps prefer the word 'pattern.' Indeed, it seems to me to denote the formed image or impression of that righteousness which Christ engraves on our hearts; and this corresponds to the prescribed rule of the law, according to which all our actions ought to be ordered, so that they do not deviate either to the right or to the left.