"I heard Abu Al-Ahwas (narrate) that 'Abdullah said: 'Defaming a Muslim is evildoing and fighting him is Kufr.'" So Aban said to him: "O Abu Ishaq! You heard it only from Abu Al-Ahwas?" He said: "Rather, I heard it from Al-Aswad and Hubairah." (Using translation from Nasāʾī 4106)
لَهُ أَبَانُ يَا أَبَا إِسْحَاقَ أَمَا سَمِعْتَهُ إِلَّا مِنْ أَبِي الْأَحْوَصِ؟ قَالَ بَلَى سَمِعْتُهُ مِنَ الْأَسْوَدِ وَهُبَيْرَةَ
"I heard Abu Al-Ahwas (narrate) that 'Abdullah said: 'Defaming a Muslim is evildoing and fighting him is Kufr.'" So Aban said to him: "O Abu Ishaq! You heard it only from Abu Al-Ahwas?" He said: "Rather, I heard it from Al-Aswad and Hubairah."
سِبَابُ الْمُسْلِمِ فِسْقٌ وَقِتَالُهُ كُفْرٌ فَقَالَ لَهُ أَبَانُ يَا أَبَا إِسْحَاقَ أَمَا سَمِعْتَهُ إِلاَّ مِنْ أَبِي الأَحْوَصِ قَالَ بَلْ سَمِعْتُهُ مِنَ الأَسْوَدِ وَهُبَيْرَةَ