2 Timothy 2:3-5

Take with me your share of hardship [passing through the difficulties which you are called to endure], like a good soldier of Christ Jesus. No soldier in active service gets entangled in the [ordinary business] affairs of civilian life; [he avoids them] so that he may please the one who enlisted him to serve. And if anyone competes as an athlete [in competitive games], he is not crowned [with the wreath of victory] unless he competes according to the rules.