A man was often cheated in buying. The Prophet ﷺ said to him, "When you buy something, say (to the seller), No cheating." The man used to say so thenceforward .
لَهُ النَّبِيُّ ﷺ إِذَا بَايَعْتَ فَقُلْ لاَ خِلاَبَةَ فَكَانَ يَقُولُهُ
A man came to the Prophet ﷺ and said, "I am often betrayed in bargaining." The Prophet ﷺ advised him, "When you buy something, say (to the seller), 'No deception." The man used to say so afterwards.
رَجُلٌ لِلنَّبِيِّ ﷺ إِنِّي أُخْدَعُ فِي الْبُيُوعِ فَقَالَ إِذَا بَايَعْتَ فَقُلْ لاَ خِلاَبَةَ فَكَانَ الرَّجُلُ يَقُولُهُ
A man came to the Prophet ﷺ and said, "I am often betrayed in bargaining." The Prophet ﷺ advised him, "When you buy something, say (to the seller), 'No deception." The man used to say so afterwards. (Using translation from Bukhārī 2407)
رَجُلٌ لِلنَّبِيِّ ﷺ إِنِّي أُخْدَعُ فِي الْبَيْعِ فَقَالَ إِذَا بَايَعْتَ فَقُلْ لَا خِلَابَةَ فَكَانَ الرَّجُلُ يَقُولُهُ
Request/Fix translation
"إذا بَايَعْت فَقُلْ لا خلابةَ".