1 Corinthians 9:24-27

Know ye not that they who run in the race-course run all, but one receives the prize? Thus run in order that ye may obtain. But every one that contends for a prize is temperate in all things: they then indeed that they may receive a corruptible crown, but we an incorruptible. I therefore thus run, as not uncertainly; so I combat, as not beating the air. But I buffet my body, and lead it captive, lest after having preached to others I should be myself rejected.