Musnad Abu Ya'la al-Mawsili 146:5

Ubayd Allah ibn Umar al-Qawariri narrated to us, Yahya ibn Sa'id narrated to us, from Shu'bah, Abu al-Tayyah narrated to me, from Anas ibn Malik, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Listen and obey, even if an Abyssinian is appointed over you, as if his head were a raisin."