كتاب البيوع
7  
Business Transactions
Bulugh al-Maram 809
Narrated [Abu Hurairah (RA)]:
Allah's Messenger (ﷺ) forbade, a city-dweller to sell for a man from the desert; one to bid against another (to raise the price); that someone sell (his product) by canceling the sale of his brother; to propose (marriage) to a woman after his brother has done so; or a woman to ask to have her sister divorced in order to deprive her of what belongs to her. [Agreed upon].
وَعَنْهُ قَالَ: { نَهَى رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-أَنْ يَبِيعَ حَاضِرٌ لِبَادٍ, وَلَا تَنَاجَشُوا, وَلَا يَبِيعُ اَلرَّجُلُ عَلَى بَيْعِ أَخِيهِ, وَلَا يَخْطُبُ عَلَى خِطْبَةِ أَخِيهِ, وَلَا تُسْأَلُ اَلْمَرْأَةُ طَلَاقَ أُخْتِهَا لِتَكْفَأَ مَا فِي إِنَائِهَا } مُتَّفَقٌ عَلَيْهِ 1‏ .‏
Reference : Bulugh al-Maram 809
In-book reference : Book 7, Hadith 809
English translation : Book 7, Hadith 812
Bulugh al-Maram 809
Muslim has:
"A Muslim must not offer a price above that offered by another Muslim."
وَلِمُسْلِمٍ: { لَا يَسُمِ اَلْمُسْلِمُ عَلَى سَوْمِ اَلْمُسْلِمِ } 1‏ .‏
Reference : Bulugh al-Maram 809
In-book reference : Book 7, Hadith 809
Hadith Text
Reference