Musnad Ahmad 489:3

Yahya ibn Sa'id narrated to us, Sa'id narrated to us, from Qatadah, from Mutarrif, from 'Iyad ibn Himar, who said: I said, "O Messenger of Allah, a man from my people insults me while he is beneath me; is there any blame upon me if I take revenge against him?" He said: "The two who insult one another are two devils, who revile one another and lie about one another."