Musannaf Ibn Abi Shayba 13:957

Abu Bakr narrated to us, he said: Affan narrated to us, he said: Aban al-Attar informed us, from Yahya ibn Abi Kathir, from Ibrahim ibn Abdullah, from al-Sa’ib ibn Yazid, from Rafi’ ibn Khadij, that the Prophet, peace and blessings of Allah be upon him, said: "The earnings of the cupper are foul, and the price of a dog is foul."