Musnad Ahmad 30:2465

Yahya narrated to us, he said: Ibn Abi Dhi'b narrated to us, he said: Al-Qasim narrated to us, from Nafi' ibn Jubayr, from Abu Hurayrah, who said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "The people are followers of Quraysh in this matter; their best are followers of their best, and their worst are followers of their worst."