Sunan an-Nasa'i #4106 · The Book of Fighting [The Prohibition of Bloodshed]

Sunan an-Nasa'iIt was narrated from Shu'bah
Sunan an-Nasa'i · Book 37 · The Book of Fighting [The Prohibition of Bloodshed]
Sunan an-Nasa'i · كتاب 37 · كتاب القتال [تحريم سفك الدماء]
"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 ‏.‏
Reference : Sunan an-Nasa'i 4106In-book reference : Book 37, Hadith 141