1 Corinthians 9:20

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.

Galatians 2:12

2:12 Until certain people came from James, he had been eating with the Gentiles. But when they arrived, he stopped doing this and separated himself because he was afraid of those who were pro-circumcision.