Sayyiduna Thawban (may Allah be pleased with him) narrates: The Messenger of Allah (peace and blessings be upon him) said: "What have I to do with the Banu al-Abbas? They have split my Ummah into factions, shed its blood, and clothed it in black garments. May Allah clothe them in garments of Fire."
Hadith Referenceالمعجم الكبير للطبراني / باب الثاء / 1413