How can Paul give a long list of conduct forbidden by God, and then say, "All things are lawful for me"? Does he have a special dispensation to commit sin? Can any Christian have the same privileges Paul seems to enjoy? What does he mean, "All things are lawful for me"?
First, it is helpful to understand that the phrase is better translated as, "I have permission to do anything," "I am free to do anything," or "I may do anything." This removes the strict sense of law and legality that the word "lawful" suggests. Paul is referring to our God-given free-moral agency. This liberty to sin appears in Deuteronomy 30:15-20, where God says we are free to choose either death or life, but He commands us to choose life, clearly implying that we are also free to choose death! History reveals that mankind, under the power of Satan, human nature, and this world, has overwhelmingly chosen death, becoming slaves to wrong choices.
When God calls us, He opens our minds to our nature, the serious purpose of life, the certainty of death, and the sacrifice of Christ for us. We may freely choose to take advantage of God's offer, enter into a covenant with Him, and receive His Spirit, and He frees us from our slavery to Satan, human nature, sin, and death. This begins the process of becoming permanently free from our slavery to wrong choices. Once in this position, we can see why Paul says, in paraphrase, "As a son of God, I still have permission to do anything, but not everything is helpful, or expedient, to fulfilling God's purpose for me if I desire to fulfill the covenant and enter God's Kingdom."
He then makes the strong statement, paraphrasing verse 12, "I will not allow myself to be mastered by human nature's lustful desires. I will control myself because, otherwise, I'd just be serving myself, not God or my fellow men." I Corinthians 9:27 confirms Paul's strong desire and efforts to guard himself against sin: "But I discipline my body and bring it into subjection, lest, when I have preached to others, I myself should become disqualified."
He writes in Romans 14:22-23: "Do you have faith? Have it to yourself before God. Happy is he who does not condemn himself in what he approves. But he who doubts is condemned if he eats, because he does not eat from faith; for whatever is not from faith is sin." Happy—blessed—is the person who overcomes lust, which in reality is idolatry, because it affects the way he worships God.