Sitting among the chaos of our new place, in which we didn't even have water, Gayle and I made time to read Proverbs 24 and talk about it. 24:6 speaks of waging war for yourself, or your own war, depending on translation. She pointed out that if it's not your own war, but doing a favor to somebody else, you can pretty well count on it turning out badly. We fight for others because we are looking for a pretext to fight, and to distract ourselves from our own real business. Her thought is confirmed elsewhere in Proverbs, where we read that one who infuriates himself with strife not belonging to him is grabbing a passing dog by the ears.
A little further on, though, in verses 11-12, we read that we are to fight for those being taken away to death, because if we hide our eyes from the trouble of the helpless, God will hide from us when we are helpless - as Jesus said, the measure you measure will be measured to you again. So we see here that we are to deliver the helpless, but because it is indeed our fight - we are helpless ourselves. So we can't do this in the consciousness of our power, but only when we are frail like them. It's not charity but solidarity. If we don't know we're helpless, we're useless.