Proverbs 26:17 (NIV)
Like one who seizes a dog by the ears is a passer-by who meddles in a quarrel not his own.
My dog is just as lovable and sweet as he can be but whenever a particular young niece of mine gets around him, she can't resist pulling, poking and overall annoying my dog. He seems resigned, forlornly looking up at me as if to say "do I have to put up with all this?" A while back, she grabbed his ears and that was just too much for him; he snapped at her. He did not bite her and he does not growl at her but it was to say, "back off, enough already!"
I not sure the quarrelers in this proverb would be as patient as my dog was. When you get involved in a quarrel not your own, no matter the reason, you are liable to get bit, so to speak, by one or both of the parties involved. Think about it, quarreling itself is not a reasonable activity. We read a few days ago that we are to avoid foolish disputes. If you grab this dog's ears, it might be hard to decide whether you dare not let go or whether you dare not hold on--you lose either way.