Sayyiduna Anas bin Malik (may Allah be pleased with him) narrates: In the blessed era, the Prophet Muhammad (peace be upon him) there was a man who used to buy and sell. He had a stammer in his speech. His family members came to the service of the Prophet Muhammad (peace be upon him). They submitted, "O Messenger of Allah (peace be upon him)! Please stop so-and-so from conducting transactions because he buys and sells and he has a stammer in his speech." The Prophet Muhammad (peace be upon him) called him and forbade him from buying and selling. So he submitted, "O Prophet of Allah, I cannot manage without buying and selling." The Prophet Muhammad (peace be upon him) said: "If you do not refrain from buying and selling, then say: 'This is it and this is it, and there will be no deception.'"