Sahih al-Bukhari 2414
صحيح البخاري#2414Sahihحَدَّثَنَا مُوسَى بْنُ إِسْمَاعِيلَ، حَدَّثَنَا عَبْدُ الْعَزِيزِ بْنُ مُسْلِمٍ، حَدَّثَنَا عَبْدُ اللَّهِ بْنُ دِينَارٍ، قَالَ سَمِعْتُ ابْنَ عُمَرَ ـ رضى الله عنهما ـ قَالَ كَانَ رَجُلٌ يُخْدَعُ فِي الْبَيْعِ فَقَالَ لَهُ النَّبِيُّ صلى الله عليه وسلم " إِذَا بَايَعْتَ فَقُلْ لاَ خِلاَبَةَ ". فَكَانَ يَقُولُهُ.
Narrated Ibn `Umar: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
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 44:5