there was a man whose mental faculties were lacking, and he used to buy and sell. His family came to the Prophet and said: "O Prophet of Allah stop him." So the Prophet of Allah called him, and told him not to do that. He said: "O Prophet of Allah, I cannot bear to be away from business," He said "If you engaged in a deal then say: 'There is no intention to deceive. "' (Sahih )  

أَنَّ رَجُلاً كَانَ فِي عُقْدَتِهِ ضَعْفٌ كَانَ يُبَايِعُ وَأَنَّ أَهْلَهُ أَتَوُا النَّبِيَّ ﷺ فَقَالُوا يَا نَبِيَّ اللَّهِ احْجُرْ عَلَيْهِ فَدَعَاهُ نَبِيُّ اللَّهِ ﷺ فَنَهَاهُ فَقَالَ يَا نَبِيَّ اللَّهِ إِنِّي لاَ أَصْبِرُ عَنِ الْبَيْعِ قَالَ إِذَا بِعْتَ فَقُلْ لاَ خِلاَبَةَ  

That there was a man who was not very sensible and he would make purchases. So his family came to the Prophet ﷺ and said: "O Messenger of Allah! Stop him (from making purchases)." So Allah's Prophet ﷺ called him to prohibit him, and he said: "O Messenger of Allah! I have no patience for business." So he said: "When you are buying, say: 'Hand to hand, and no cheating.'"  

أَنَّ رَجُلاً كَانَ فِي عُقْدَتِهِ ضَعْفٌ وَكَانَ يُبَايِعُ وَأَنَّ أَهْلَهُ أَتَوُا النَّبِيَّ ﷺ فَقَالُوا يَا رَسُولَ اللَّهِ احْجُرْ عَلَيْهِ فَدَعَاهُ نَبِيُّ اللَّهِ ﷺ فَنَهَاهُ فَقَالَ يَا رَسُولَ اللَّهِ إِنِّي لاَ أَصْبِرُ عَنِ الْبَيْعِ فَقَالَ إِذَا بَايَعْتَ فَقُلْ هَاءَ وَهَاءَ وَلاَ خِلاَبَةَ  

there was a man at the time of the Messenger of Allah ﷺ whose mental faculties were lacking, and he used to buy and sell. His family came to the Prophet ﷺ and said, “O Messenger of Allah, stop him.” So The Prophet ﷺ called him, and told him not to do that. He said: “O Messenger of Allah ﷺ, I cannot bear to be away from business.” He said, “If you engage in a transaction then say: “Take it (i.e., the goods) and don't cheat (me).' ”  

أَنَّ رَجُلاً كَانَ فِي عَهْدِ رَسُولِ اللَّهِ ﷺ فِي عُقْدَتِهِ ضَعْفٌ وَكَانَ يُبَايِعُ وَأَنَّ أَهْلَهُ أَتَوُا النَّبِيَّ ﷺ فَقَالُوا يَا رَسُولَ اللَّهِ احْجُرْ عَلَيْهِ فَدَعَاهُ النَّبِيُّ ﷺ فَنَهَاهُ عَنْ ذَلِكَ فَقَالَ يَا رَسُولَ اللَّهِ إِنِّي لاَ أَصْبِرُ عَنِ الْبَيْعِ فَقَالَ إِذَا بَايَعْتَ فَقُلْ هَا وَلاَ خِلاَبَةَ