1 Corinthians 9:19-27
For though I am free with respect to all, I have made myself a slave to all, so that I might win more of them. 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 I myself am not under the law) so that I might win those under the law. To those outside the law I became as one outside the law (though I am not free from God's law but am under Christ's law) so that I might win those outside the law. To the weak I became weak, so that I might win the weak. I have become all things to all people, that I might by all means save some. I do it all for the sake of the gospel, so that I may share in its blessings.
Do you not know that in a race the runners all compete, but only one receives the prize? Run in such a way that you may win it. Athletes exercise self-control in all things; they do it to receive a perishable wreath, but we an imperishable one. So I do not run aimlessly, nor do I box as though beating the air; but I punish my body and enslave it, so that after proclaiming to others I myself should not be disqualified.