Narrated from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) that an Ansari or a Qurayshi man used to be deceived in business transactions, and he had a stammer in his speech. So he complained to the Messenger of Allah (peace and blessings be upon him) about the loss he suffered. The Prophet (peace and blessings be upon him) said to him: When you are about to make a deal, say:“No deception.”Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) says: By Allah! It is as if I am still hearing him stammering and saying:“No deception.”