2 Timothy 2:2-5

The things which you have heard from me in the presence of many witnesses, entrust these to faithful men who will be able to teach others also. Suffer hardship with me, as a good soldier of Christ Jesus. No soldier in active service entangles himself in the affairs of everyday life, so that he may please the one who enlisted him as a soldier. Also if anyone competes as an athlete, he does not win the prize unless he competes according to the rules.