Christian Liberty

http://www.macarthurcommentaries.com ... All things are lawful for me, but not all things are profitable. All things are lawful for me, but I will not be mastered by anything. (1 Corinthians 6:12)
The statement, All things are lawful may have been a common Corinthian saying in that liberated society. Paul borrows it and, playing off it, says, "It is so for me, too. Every sin I as a Christian commit is forgiven in Jesus Christ." But no sin is ever right or good, and no sin ever produces anything right or good. Sin can never be worthwhile or profitable. Profitable (sumphero) means "to be to advantage." In the sense that believers are free and no longer under the penalty of the law in any way, all things are lawful for them. But the price for doing some things is terribly high, terribly unprofitable. Sin never brings profit; it always brings loss.

All things are lawful for me, but I will not be mastered by anything. Paul was free in the grace of Christ to do as he pleased, but he refused to allow himself to be mastered by anything or anyone but Christ. He would not become enslaved to any habit or custom and certainly not to any sin. "For sin shall not be master over you, for you are not under law, but under grace" (Rom. 6:14)...