Narrated by:Shu'bah
It was narrated from Shu'bah, from Abu Ishaq who said:"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."
أَخْبَرَنَا يَحْيَى بْنُ حَكِيمٍ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، عَنْ شُعْبَةَ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي الأَحْوَصِ، عَنْ عَبْدِ اللَّهِ، قَالَ سِبَابُ الْمُسْلِمِ فِسْقٌ وَقِتَالُهُ كُفْرٌ . فَقَالَ لَهُ أَبَانُ يَا أَبَا إِسْحَاقَ أَمَا سَمِعْتَهُ إِلاَّ مِنْ أَبِي الأَحْوَصِ قَالَ بَلْ سَمِعْتُهُ مِنَ الأَسْوَدِ وَهُبَيْرَةَ .
Nesai
The Book of Fighting [The Prohibition of Bloodshed] • Hadith 4106