Musannaf Ibn Abi Shayba 13:2463

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Qasim al-Ju’fi narrated to us, from his father, from Maymun ibn Mihran, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Trading is by mutual consent, and the option (to rescind) is after the transaction. And it is not lawful for a Muslim to defraud a Muslim."