Sayyiduna Hakim bin Hizam (may Allah be pleased with him) narrated that the Messenger of Allah (peace and blessings be upon him) said: The buyer and the seller have the option (to cancel the sale) as long as they have not separated, or he said: until they both separate. (The Messenger of Allah, peace and blessings be upon him, further said:) So if both speak the truth and clarify everything, there is blessing in their transaction, but if they conceal something or tell a lie, the blessing of their transaction is erased.