20 To the Jews I became like a Jew, to win the Jews. To those under the law I became like one under the law (though I myself am not under the law), so as to win those under the law.

Read 1 Corinthians 9:20 Using Other Translations

And unto the Jews I became as a Jew, that I might gain the Jews; to them that are under the law, as under the law, that I might gain them that are under the law;
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.
When I was with the Jews, I lived like a Jew to bring the Jews to Christ. When I was with those who follow the Jewish law, I too lived under that law. Even though I am not subject to the law, I did this so I could bring to Christ those who are under the law.