The key phrase in this passage is All things are lawful for me. It occurs twice in this verse, and shows up again in 10-23, without the -for me.- Paul quotes the phrase like a motto, in order to put it in the proper perspective.--All things are lawful for me is a particularly Christian statement in one important sense. All other religions prescribe rules which must be kept for a person to have a chance to be saved. They are all systems of gaining righteousness and holiness through human effort. Christianity is unique. It is a matter of salvation by divine accomplishment rather than by human effort. Every other religious systems says You must DO. The Bible says God has DONE it.--Like any pithy statement, All things are lawful for me is subject to being misinterpreted.