Musnad Abu Ya'la al-Mawsili 3:221

Abu Khaythama narrated to us, he said: Isma'il ibn Ibrahim narrated to us, from Ayyub, from Muhammad, from 'Ubayda, from 'Ali, who said: He mentioned the Khawarij, and he said regarding them: "A man with a stunted hand, or a deformed hand, or a defective hand. Were it not that you would become arrogant, I would tell you what Allah has promised those who kill them upon the tongue of Muhammad." He said: I said, "Did you hear it from Muhammad?" He said: "Yes, and the Lord of the Ka'bah. Yes, and the Lord of the Ka'bah. Yes, and the Lord of the Ka'bah."