Musnad Ahmad 30:942

'Abd al-Razzaq narrated to us, Ma'mar informed us, from Ayyub, from Ghaylan ibn Jarir, from Ziyad ibn Riyah, from Abu Hurayrah, who said: I heard the Messenger of Allah (peace and blessings of Allah be upon him) saying: "Whoever separates from the community and exits from obedience, then dies, his death is a death of Jahiliyyah (pre-Islamic ignorance). And whoever revolts against my community with his sword, striking its righteous and its wicked, not sparing a believer for his belief, and not fulfilling a covenant for one who has a covenant, then he is not of my community. And whoever is killed under a blind banner, becoming angry for the sake of tribalism, or fighting for the sake of tribalism, or calling to tribalism, then his killing is a killing of Jahiliyyah."