Musnad Ahmad 907:55

Hashim narrated to us, Zuhayr narrated to us, Ziyad ibn Khaythamah narrated to us, from al-Aswad ibn Sa'id al-Hamdani, from Jabir ibn Samurah, who said: I heard the Messenger of Allah, may Allah bless him and grant him peace, or he said: The Messenger of Allah, may Allah bless him and grant him peace, said: "There will be twelve caliphs after me, all of them from Quraysh." He said: Then he returned to his house, and the Quraysh came to him and said: Then what will happen? He said: "Then there will be al-harj (bloodshed/turmoil)."