Musnad Ahmad 27:1395

Waki’ narrated to us, Abdullah ibn Nafi’ narrated to me, from his father, from Safiyyah bint Abi ‘Ubayd, who said: Ibn Umar saw a young boy who had *qaza’* (shaved patches) on his head. He said: "Do you not know that the Messenger of Allah (peace and blessings of Allah be upon him) forbade shaving the *qaza’* of young boys?"