Romans 6:17 - Matthew Poole's English Annotations on the Holy Bible

But God be thanked, that ye were the servants of sin: q.d. But as for you, God be thanked, that though once you were the servants of sin, viz. when you were ignorant and unregenerate, yet now you are freed from that bondage, and set at liberty from the power and dominion of sin. But ye have obeyed from the heart that form of doctrine which was delivered you: this phrase expresses the efficacy of Divine doctrine in the hearts of believers; it changeth and fashioneth their hearts according to its likeness, 2 Corinthians 3:18. Hence in James 1:21, it is called an ingrafted word; it turns the heart and life of the hearer into its own nature, as the stock doth the scion that is ingrafted into it. The doctrine of the gospel is the mould, and the hearer is the metal, which, when it is melted and cast into the mould, receives its form and figure.