Musannaf Ibn Abi Shayba 13:2237

Abu Bakr narrated to us, he said: Yazid ibn Harun narrated to us, he said: Muhammad ibn Talha narrated to us, from Muhammad ibn Jahada, from Zadhan, who said: Ali used to come to the marketplace and greet [the people]. Then he would say: "O assembly of merchants, beware of excessive swearing in selling, for it promotes the commodity but wipes out the blessing."