Musannaf Ibn Abi Shayba 16:867

Abu Bakr narrated to us, he said: Mubarak narrated to us, from Hisham, from Abu Qudamah, who said: A man entered upon Ibn Sirin while he had long hair, so he said: "This is disliked." Then he entered upon him the next day, and he had shaved it off completely, so he said: "This is disliked."