Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) narrates: A man was mentioned before the Prophet (peace and blessings of Allah be upon him) who used to be deceived in buying and selling, so the Prophet (peace and blessings of Allah be upon him) said to him: "When you make a transaction with someone, say: 'There will be no deception.'" So whenever that man made a transaction, he would say: "There will be no deception."