You are provoked by abuse as by something repulsive? Pretend to yourself it is something good. Otherwise you do what you complain of. Or is it that you look carefully at the evils others commit, and think nothing of your own wickedness? Is such abuse not an evil thing? Then fly from imitating it. That another began it is no excuse. Indeed to me it seems more fitting to blame you for the quarrel; in that you gave him no example in self restraint. You see an angry man behaving in an unbecoming manner do not guard against imitating him, but becoming angry and bitter you rage against him; so your anger now becomes a justification for the one who began the quarrel. And in doing this you provide an excuse for him, and condemn yourself.
St. Basil the Great
"Against the Angry"