It was narrated from Anas that there was a man whose mental faculties were lacking, and he used to buy and sell. His family came to the Prophet صلی اللہ علیہ وآلہ وسلم and said: “Prophet of Allah صلی اللہ علیہ وآلہ وسلم; stop him.” So the Prophet of Allah صلی اللہ علیہ وآلہ وسلم called him, and told him not to do that. He said: “Prophet of Allah صلی اللہ علیہ وآلہ وسلم, I cannot bear to be away from business.” He said, “If you engage in a deal, then say: ‘There is no intention to deceive.” (Sahih)