Bible Basics: Made Free from Sin
Paul wrote, "But God be thanked, that ye were the servants of sin, but ye have obeyed from the heart that form of doctrine which was delivered you. Being then made free from sin, ye became the servants of righteousness" (Rom. 6:17, 18). What a blessing to be free from sin! Awareness of guilt causes one to long for freedom-freedom from a consciousness of being rejected by the Lord.
Paul thanks God for this freedom (Rom. 6:17; 7:25). Salvation is from and of the Lord (cf. Jonah 2:9; Eph. 2:8-10). Paul here emphasizes both the fact of all being bondmen to sin and the possibility of freedom to all.
A "form of doctrine" had been delivered to these Romans. This was simply the gospel preached to them. It embraced the facts of His (Christ's) death, burial, and resurrection (1 Cor. 15:1-4). Furthermore, it embraced His commandments which, when obeyed, freed sinners. Jesus commissioned the apostles to preach His gospel to every creature (Mk. 16:15, 16), which gospel demanded all sinners to believe the gospel, repent of their sins and be baptized in water for the remission of their sins (Mk. 16:15, 16; Acts 2:38). No sinner can be freed from sin without the gospel. Sinners can hear and understand the gospel, some denominational preachers to the contrary, notwithstanding (Eph. 3:1-6).
This text shows this obedience to be "from the heart." These people had sincerely and willingly yielded to the molding efficacy of this form of doctrine. The word "form" comes from the Greek tupos (in this passage it is accusative singular tupon), and is said to be "the teaching which embodies the sum and substance of religion and represents it to the mind" (Thayer, p. 632). Form, mold, pattern is the idea. As the truth is taught to one and his mind accepts it, this is that yielding to the forming power of that gospel. It will change one-change one from servants of sin to servants of righteousness.
However, we must notice that this change comes only to the ones who "obey from the heart." "Obey" is action on the part of the sinner. Often we hear some preacher say sinners can not obey. They even tell us that action on the sinner's part makes void the grace of God! That is not what this passage says. This verse says we are made free from sin when we obey the gospel of Christ. See Romans 1:16.
Truth Magazine XXII: 17, p. 279