About vengeance: from the desert
A brother who was insulted by another brother came to Abba Sisoes, and said to him: I was hurt by my brother, and I want to avenge myself. The old man tried to console him and said: Don't do that, my child. Rather leave vengeance to God. But he said: I will not quit until I avenge myself. Then the old man said: Let us pray, brother; and standing up, he said: O God, we no longer need you to take care of us since we now avenge ourselves. Hearing these words, the brother fell at the feet of the old man and said: I am not going to fight with my brother any more. Forgive me, Abba.