أَخْبَرَنَا نُعَيْمُ بْنُ حَمَّادٍ ، عَنْ عَبْدِ الْعَزِيزِ بْنِ مُحَمَّدٍ ، عَنْ الْعَلَاءِ ، عَنْ أَبِيهِ ، عَنْ أَبِي هُرَيْرَةَ ، عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَنَّهُ قِيلَ لَهُ : مَا الْغِيبَةُ؟.
قَالَ : " ذِكْرُكَ أَخَاكَ بِمَا يَكْرَهُ ".
قِيلَ : وَإِنْ كَانَ فِي أَخِي مَا أَقُولُ؟.
قَالَ :" فَإِنْ كَانَ فِيهِ، فَقَدْ اغْتَبْتَهُ، وَإِنْ لَمْ يَكُنْ فِيهِ، فَقَدْ بَهَتَّهُ "

Nu'aym bin Hammad told us, on the authority of Abdul Aziz bin Muhammad, on the authority of Al-Ala', on the authority of his father, on the authority of Abu Hurairah, on the authority of the Prophet, may God bless him and grant him peace. He acknowledged that it was said to him: What is backbiting?
He said: “He mentioned your brother in a way that he dislikes.”
It was said: What should I say about my brother?
He said: “If it was about him, then you backbited him, and if it was not about him, then you slandered him.”