Sahih Muslim 14728
In-book no 7451حَدَّثَنِي عَمْرُو بْنُ عَلِيٍّ، وَحَسَنٌ الْحُلْوَانِيُّ، كِلاَهُمَا عَنْ عَفَّانَ بْنِ مُسْلِمٍ، قَالَ كُنَّا عِنْدَ إِسْمَاعِيلَ ابْنِ عُلَيَّةَ فَحَدَّثَ رَجُلٌ، عَنْ رَجُلٍ، فَقُلْتُ إِنَّ هَذَا لَيْسَ بِثَبْتٍ . قَالَ فَقَالَ الرَّجُلُ اغْتَبْتَهُ . قَالَ إِسْمَاعِيلُ مَا اغْتَابَهُ . وَلَكِنَّهُ حَكَمَ أَنَّهُ لَيْسَ بِثَبْتٍ .
Amr bin Alī and Hasan al-Hulwānī narrated to me, both of them on authority of Affān bin Muslim, he said: ‘We were near Ismā’īl bin Ulayyah, and a man narrated on authority of another man, so I said: ‘Indeed this is not reliable (Thabt)’. So the man said: ‘Are you backbiting him?’ Ismā’īl said: ‘He is not backbiting him; rather he is judging him unreliable’.