From Paul’s Passing Thoughts, The Problem with Wartburg:
ALL people on the earth are slaves. They are either slaves to unrighteousness or slaves to righteousness. AND, all people upon the earth are also free, and the freedom corresponds to the slavery. The unregenerate are enslaved to disobedience and free to obey (Romans 6:20)—the regenerate are enslaved to obedience and free to sin. No unbeliever sins perfectly, and no believer obeys perfectly.