Musannaf Ibn Abi Shayba 13:1329

Abu Bakr narrated to us, he said: Mu'adh ibn Mu'adh narrated to us, from Ash'ath, from al-Hasan, regarding a man who buys slaves and finds a defect in some of them. He said: He returns them for their value. And in merchandise, it is the same. And Muhammad said it.