Musnad Ahmad 30:2805

'Abd al-Rahman narrated to us, Shu'bah narrated to us, and Hajjaj said: Shu'bah informed us, from 'Abdullah ibn Yazid—Hajjaj said: from the Nakha'—he said: I heard Abu Zur'ah, from Abu Hurayrah, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Name yourselves with my name, but do not take my kunyah (agnomen)." "And he used to dislike the *shikal* of horses." Hajjaj said: "Meaning one of its legs is black or white."