Abu Huraira reported Allah's Messenger (ﷺ) as saying:Don't nurse grudge and don't bid him out for raising the price and don't nurse aversion or enmity and don't enter into a transaction when the others have entered into that transaction and be as fellow-brothers and servants of Allah. A Muslim is the brother of a Muslim. He neither oppresses him nor humiliates him nor looks down upon him. The piety is here, (and while saying so) he pointed towards his chest thrice. It is a serious evil for a Muslim that he should look down upon his brother Muslim. All things of a Muslim are inviolable for his brother in faith: his blood, his wealth and his honour.
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ بْنِ قَعْنَبٍ، حَدَّثَنَا دَاوُدُ، - يَعْنِي ابْنَ قَيْسٍ - عَنْ أَبِي، سَعِيدٍ مَوْلَى عَامِرِ بْنِ كُرَيْزٍ عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ تَحَاسَدُوا وَلاَ تَنَاجَشُوا وَلاَ تَبَاغَضُوا وَلاَ تَدَابَرُوا وَلاَ يَبِعْ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ وَكُونُوا عِبَادَ اللَّهِ إِخْوَانًا . الْمُسْلِمُ أَخُو الْمُسْلِمِ لاَ يَظْلِمُهُ وَلاَ يَخْذُلُهُ وَلاَ يَحْقِرُهُ . التَّقْوَى هَا هُنَا " . وَيُشِيرُ إِلَى صَدْرِهِ ثَلاَثَ مَرَّاتٍ " بِحَسْبِ امْرِئٍ مِنَ الشَّرِّ أَنْ يَحْقِرَ أَخَاهُ الْمُسْلِمَ كُلُّ الْمُسْلِمِ عَلَى الْمُسْلِمِ حَرَامٌ دَمُهُ وَمَالُهُ وَعِرْضُهُ " .
Muslim
The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship • Hadith 40