I Corinthians 9:24-27

24. Do you not know that in a race all the runners run, but only one gets the prize? Run in such a way as to get the prize.
25. Everyone who competes in the games goes into strict training. They do it to get a crown that will not last; but we do it to get a crown that will last forever.
26. Therefore I do not run like a man running aimlessly; I do not fight like a man beating the air.
27. No, I beat my body and make it my slave so that after I have preached to others, I myself will not be disqualified for the prize.