Sunan Ibn Majah, Volume 3, Book 12, Hadith 2171 (DarusSalam) ⓘ
It was narrated from Ibn 'Umar that the Messenger of Allah said: "Let one of you not undersell another."[1]
حَدَّثَنَا 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 " .
also referenced under: Hadith 2171 (Reference) & Book 12, Hadith 2255 (In-Book)