1 Corinthians 9:18-20 English Standard Version (ESV)

18. What then is my reward? That in my preaching I may present the gospel free of charge, so as not to make full use of my right in the gospel.

19. For though I am free from all, I have made myself a servant to all, that I might win more of them.

20. To the Jews I became as a Jew, in order to win Jews. To those under the law I became as one under the law (though not being myself under the law) that I might win those under the law.

1 Corinthians 9