Sunan an-Nasa'i 4484
سنن النسائي#4484Sahihأَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، عَنْ مَالِكٍ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَجُلاً، ذَكَرَ لِرَسُولِ اللَّهِ صلى الله عليه وسلم أَنَّهُ يُخْدَعُ فِي الْبَيْعِ فَقَالَ لَهُ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا بِعْتَ فَقُلْ لاَ خِلاَبَةَ " . فَكَانَ الرَّجُلُ إِذَا بَاعَ يَقُولُ لاَ خِلاَبَةَ .
It was narrated from Ibn 'Umar that:a man told the Messenger of Allah that he was always being cheated. The Messenger of Allah said to him: "When you make a deal, say: There is no intention of cheating" So, whenever the man engages in a deal he says, 'There is no intention of cheating." "(Sahih)
Scholarly Authentication
The label above is the grade most of these scholars gave, each scholar counted once — 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. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:
Our source also lists this ruling under Abu Ghuddah, the editor of the printed edition it was taken from. It is al-Albani's ruling printed again, so it is counted once.
In-book reference: 44:36