Romans 6:18

Being ... made free. Literally, “having been freed,” or “having been set free,” that is, delivered from the dominion of sin.

Became the servants. Or, “were enslaved.” Conversion means a change of masters. The believer is released from slavery to the tyrant sin and becomes a slave of righteousness. But slavery to righteousness is actually real freedom. Those who serve sin and Satan are the slaves of their own impulses and passions, which in turn are under the control of the wicked one. In calling men to serve righteousness, God is offering them freedom. “Obedience to God is liberty from the thralldom of sin, deliverance from human passion and impulse” (Ministry of Healing, p. 131).