Servant unto all— This is very emphatical, and intimates that he acted with as self-denying a regard to their interests, and as much caution not to offend them, as if he were absolutely in their power,—as a slave is in that of his master. See Doddridge.
Related Commentaries of 1 Corinthians 9:19
1 Corinthians 9:19
19 For though I be free from all men, yet have I made myself servant unto all, that I might gain the more.