1 Corinthians 9:19-20

9:19 For since I am free from all I can make myself a slave to all, in order to gain even more people. 9:20 To the Jews I became like a Jew to gain the Jews. To those under the law I became like one under the law (though I myself am not under the law) to gain those under the law.

1 Corinthians 9:22

9:22 To the weak I became weak in order to gain the weak. I have become all things to all people, so that by all means I may save some.