1 Corinthians 9:24-27

24Do you not know that all the runners in a stadium compete, but only one receives the prize? So run to win.

25Each competitor must exercise self-control in everything. They do it to receive a perishable crown, but we an imperishable one.

26So I do not run uncertainly or box like one who hits only air.

27Instead I subdue my body and make it my slave, so that after preaching to others I myself will not be disqualified.