I Corinthians 9:23-27

Now this I do for the gospel’s sake, that I may be partaker of it with you. Do you not know that those who run in a race all run, but one receives the prize? Run in such a way that you may obtain it. And everyone who competes for the prize is temperate in all things. Now they do it to obtain a perishable crown, but we for an imperishable crown. Therefore I run thus: not with uncertainty. Thus I fight: not as one who beats the air. But I discipline my body and bring it into subjection, lest, when I have preached to others, I myself should become disqualified.