1 Corinthians 9:19-23

For whereas I was free as to all, I made myself the servant of all, that I might gain the more. And I became to the Jews, a Jew, that I might gain the Jews: To them that are under the law, as if I were under the law, (whereas myself was not under the law,) that I might gain them that were under the law. To them that were without the law, as if I were without the law, (whereas I was not without the law of God, but was in the law of Christ,) that I might gain them that were without the law. To the weak I became weak, that I might gain the weak. I became all things to all men, that I might save all. And I do all things for the gospel's sake: that I may be made partaker thereof.