Muwatta Malik 1381
موطأ مالك#1381Sahihقَالَ مَالِكٌ عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنِ النَّجْشِ .
Malik said, from Nafi from Abdullah ibn Umar that the Messenger of Allah, may Allah bless him and grant him peace, forbade najsh. Malik said, "Najsh is to offer a man more than the worth of his goods when you do not mean to buy them and someone else follows you in bidding
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:
Salim al-HilaliSahih
In-book reference: 31:43