Sunan Ibn Majah 2171
سنن ابن ماجه#2171Sahihحَدَّثَنَا سُوَيْدُ بْنُ سَعِيدٍ، حَدَّثَنَا مَالِكُ بْنُ أَنَسٍ، عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ ـ صلى الله عليه وسلم ـ قَالَ " لاَ يَبِيعُ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ " .
It was narrated from Ibn 'Umar that the Messenger of Allah (ﷺ) said:"Let one of you not undersell another
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:
Al-AlbaniSahih
Muhammad Fouad Abd al-BaqiSahih
Shuaib Al ArnautSahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 12:35