In the name of Allah, Most Gracious, Most Merciful.
Abu Hurairah (May Allah be pleased with him) said: The Messenger of Allah (May Allah exalt his mention and protect him from imperfection) said: “Beware of suspicion, for suspicion is the worst of false tales. Do not look for others faults. Do not spy one another, and do not practice Najsh (means to offer a high price for something in order to allure another customer who is interested in the thing). Do not be jealous of one another and do not nurse enmity against one another. Do not sever ties with one another. Become the slaves of Allah, and be brothers to one another as He commanded. A Muslim is the brother of a Muslim. He should neither oppress him nor humiliate him. The piety is here! The piety is here! While saying so he pointed towards his chest. “It is enough evil for a Muslim to look down upon his Muslim brother. All things of a Muslim are inviolable for his brother in Faith: his blood, his wealth and his honor. Verily, Allah does not look to your bodies nor to your faces but He looks to your hearts and your deeds.” (Muslim)
Riyaadiss-Saliheen (The Meadows of the Righteous)
By Imam An Nawawi
Chapter 271, Page 453, No 1570