1 Corinthians 9:19-27

For though I am free from all men, I have made myself a slave to everyone, so that I may win more [for Christ]. To the Jews I became as a Jew, so that I might win Jews [for Christ]; to men under the Law, [I became] as one under the Law, though not being under the Law myself, so that I might win those who are under the Law. To those who are without (outside) the Law, [I became] as one without the Law, though [I am] not without the law of God, but under the law of Christ, so that I might win those who are without law. To the weak I became [as the] weak, to win the weak. I have become all things to all men, so that I may by all means [in any and every way] save some [by leading them to faith in Jesus Christ]. And I do all this for the sake of the gospel, so that I may share in its blessings along with you. Do you not know that in a race all the runners run [their very best to win], but only one receives the prize? Run [your race] in such a way that you may seize the prize and make it yours! Now every athlete who [goes into training and] competes in the games is disciplined and exercises self-control in all things. They do it to win a crown that withers, but we [do it to receive] an imperishable [crown that cannot wither]. Therefore I do not run without a definite goal; I do not flail around like one beating the air [just shadow boxing]. But [like a boxer] I strictly discipline my body and make it my slave, so that, after I have preached [the gospel] to others, I myself will not somehow be disqualified [as unfit for service].