Muwatta Malik, Book 31, Hadith 98 (USC-MSA) ⓘ
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."
قَالَ مَالِكٌ عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم نَهَى عَنِ النَّجْشِ .
also referenced under: Book 31, Hadith 1384 (In-Book)