Hadith 8:89
Abu Huraira reported God’s Messenger as saying, “A man must not offer a price above that offered by his brother Muslim.” Muslim transmitted it.
وَعَنْ أَبِي هُرَيْرَةَ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «لَا يَسُمِ الرَّجُلُ على سَوْمِ أخيهِ الْمُسلم» . رَوَاهُ مُسلم
Original Reference: Mishkat al-Masabih 2851