It is narrated from Hazrat Anas (may Allah be pleased with him) that during the blessed era of the Prophet (peace and blessings be upon him), there was a man "who had some weakness in his intellect" and used to buy and sell (and would be deceived). His family members came to the service of the Prophet (peace and blessings be upon him) and said, O Messenger of Allah (peace and blessings be upon him)! Impose a restriction on so-and-so regarding buying and selling because his intellect is weak. The Prophet (peace and blessings be upon him) called him and forbade him from buying and selling. He said, O Messenger of Allah! I cannot refrain from this work. The Prophet (peace and blessings be upon him) said, If you cannot leave buying and selling, then when making a transaction, say: "There is no deception in this transaction."