Sahih Muslim , Book 21, Hadith 11 (In-Book) ⓘ
Ibn 'Umar (Allah be pleased with them) reported Allah's Messenger as having said this: One amongst you should not enter into a transaction when another is bargaining.
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ نَافِعٍ، عَنِ ابْنِ عُمَرَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " لاَ يَبِعْ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ " .
also referenced under: Hadith 1412 (Reference) & Book 10, Hadith 3617 (USC-MSA)