1 Corinthians 9:24-27New American Standard Bible (NASB)
24 Do you not know that those who run in a race all run, but only one receives the prize? Run in such a way that you may win. 25 Everyone who competes in the games exercises self-control in all things. They then do it to receive a perishable wreath, but we an imperishable. 26 Therefore I run in such a way, as not without aim; I box in such a way, as not beating the air; 27 but I discipline my body and make it my slave, so that, after I have preached to others, I myself will not be disqualified.
