Musannaf Ibn Abi Shayba 13:2949

Abu Bakr narrated to us, he said: Waki' narrated to us, he said: Ibn 'Awn narrated to us, he said: I said to Muhammad ibn Sirin: "Shall I buy with a counterfeit dirham and then clarify it [to the seller]?" He said: "There is no harm in it."