Abu Hurayrah (may Allah be pleased with him) narrated that the Prophet (peace and blessings be upon him) said: "Whoever leaves obedience and separates from the community (jama'ah), and dies in that state, has died the death of jahiliyyah. Whoever fights under a banner of 'ummiyyah' (blind cause), becoming angry for tribal partisanship, calling to tribal partisanship or supporting tribal partisanship, and is killed, his killing is a killing of jahiliyyah. And whoever rises against my Ummah, striking down its righteous and its wicked alike, not sparing its believers and not keeping faith with those under its covenant, he is not of me and I am not of him."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب قتال أهل البغي / 16611