1 Corinthians 9:19

The apostle takes occasion from what he had before discoursed to mention some other instances of his self-denial and parting with his liberty for the benefit of others. I. He asserts his liberty (Co1 9:19): Though I be free from all men. He was free-born, a citizen of Rome. He was in bondage to none, nor depended upon any for his subsistence; yet he made himself a servant to all, that he might gain the more. He behaved as a servant; he laboured for their good as a servant; he was careful to please, as a servant to his master; he acted in many cases as if he had no privileges; and this that he might gain the more, or make the more converts to Christianity. He made himself a servant, that they might be made free. II. He specifies some particulars wherein he made himself a servant to all. He accommodated himself to all sorts of people. 1. To the Jews, and those under the law, he became a Jew, and as under the law, to gain them. Though he looked on the ceremonial law as a yoke taken off by Christ, yet in many instances he submitted to it, that he might work upon the Jews, remove their prejudices, prevail with them to hear the gospel, and win them over to Christ. 2. To those that are without the law as without law that is, to the Gentiles, whether converted to the Christian faith or not.

— Matthew Henry's Concise Commentary (public domain)

free from all men--that is, from the power of all men. gain the more--that is, as many of them ("all men") as possible. "Gain" is an appropriate expression in relation to a "reward" (Th1 2:19-20); he therefore repeats it frequently (Co1 9:20-22).

— Jamieson-Fausset-Brown Commentary (public domain)