Hadith 35, 40 Hadith an-Nawawi
On the authority of Abu Hurayrah (may Allah be pleased with him) who said:
The Messenger of Allah (peace and blessings of Allah be upon him) said, “Do not envy one another, and do not inflate prices for one another, and do not hate one another, and do not turn away from one another, and do not undercut one another in trade, but [rather] be slaves of Allah and brothers [amongst yourselves]. A Muslim is the brother of a Muslim: he does not oppress him, nor does he fail him, nor does he lie to him, nor does he hold him in contempt. Taqwa (piety) is right here [and he pointed to his chest three times]. It is evil enough for a man to hold his brother Muslim in contempt. The whole of a Muslim is inviolable for another Muslim: his blood, his property, and his honour.” [Muslim]
عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صلى الله عليه و سلم " لَا تَحَاسَدُوا، وَلَا تَنَاجَشُوا، وَلَا تَبَاغَضُوا، وَلَا تَدَابَرُوا، وَلَا يَبِعْ بَعْضُكُمْ عَلَى بَيْعِ بَعْضٍ، وَكُونُوا عِبَادَ اللَّهِ إخْوَانًا، الْمُسْلِمُ أَخُو الْمُسْلِمِ، لَا يَظْلِمُهُ، وَلَا يَخْذُلُهُ، وَلَا يَكْذِبُهُ، وَلَا يَحْقِرُهُ، التَّقْوَى هَاهُنَا، وَيُشِيرُ إلَى صَدْرِهِ ثَلَاثَ مَرَّاتٍ، بِحَسْبِ امْرِئٍ مِنْ الشَّرِّ أَنْ يَحْقِرَ أَخَاهُ الْمُسْلِمَ، كُلُّ الْمُسْلِمِ عَلَى الْمُسْلِمِ حَرَامٌ: دَمُهُ وَمَالُهُ وَعِرْضُهُ" . 
[رَوَاهُ مُسْلِمٌ].