It is narrated from Sayyiduna Hakim bin Hizam (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said:“The buyer and the seller have the option (to cancel the transaction) as long as they have not separated. Then, if both speak the truth and clarify everything, there will be blessing in their trade (buying and selling), but if both lie and conceal something, the blessing in their transaction will be erased.”