Lawful (εξεστιν). Apparently this proverb may have been used by Paul in Corinth (repeated in 1 Corinthians 10:23), but not in the sense now used by Paul's opponents. The "all things" do not include such matters as those condemned in chapter 1 Corinthians 6:1; 1 Corinthians 6:1-11. Paul limits the proverb to things not immoral, things not wrong per se. But even here liberty is not license.

But not all things are expedient (αλλ' ου παντα συμφερε). Old word συμφερε, bears together for good and so worthwhile. Many things, harmless in themselves in the abstract, do harm to others in the concrete. We live in a world of social relations that circumscribe personal rights and liberties.

But I will not be brought under the power of any (αλλ ουκ εγω εξουσιασθησομα υπο τινος). Perhaps a conscious play on the verb εξεστιν for εξουσιαζω is from εξουσιαand that from εξεστιν. Verb from Aristotle on, though not common (Dion. of Hal., LXX and inscriptions). In N.T. only here, 1 Corinthians 7:4; Luke 22:25. Paul is determined not to be a slave to anything harmless in itself. He will maintain his self-control. He gives a wholesome hint to those who talk so much about personal liberty.