Sahih Muslim 2589
Sahih Muslim · Book 45: The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship · The Prohibition Of Backbiting
Abu Huraira reported Allah's Messenger (ﷺ) as saying:
حَدَّثَنَا يَحْيَى بْنُ أَيُّوبَ ، وَقُتَيْبَةُ ، وَابْنُ، حُجْرٍ قَالُوا حَدَّثَنَا إِسْمَاعِيلُ ، عَنِ الْعَلاَءِ ، عَنْ أَبِيهِ ، عَنْ أَبِي هُرَيْرَةَ ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " أَتَدْرُونَ مَا الْغِيبَةُ " . قَالُوا اللَّهُ وَرَسُولُهُ أَعْلَمُ . قَالَ " ذِكْرُكَ أَخَاكَ بِمَا يَكْرَهُ " . قِيلَ أَفَرَأَيْتَ إِنْ كَانَ فِي أَخِي مَا أَقُولُ قَالَ " إِنْ كَانَ فِيهِ مَا تَقُولُ فَقَدِ اغْتَبْتَهُ وَإِنْ لَمْ يَكُنْ فِيهِ فَقَدْ بَهَتَّهُ " .
Do you know what is backbiting? They (the Companions) said: Allah and His Messenger know best. Thereupon he (the Holy Prophet) said: Backbiting implies your talking about your brother in a manner which he does not like. It was said to him: What is your opinion about this that if I actually find (that failing) in my brother which I made a mention of? He said: If (that failing) is actually found (in him) what you assert, you in fact backbited him, and if that is not in him it is a slander.