Sunan an-Nasa'i 4113

سنن النسائي#4113Sahih

أَخْبَرَنَا مُحَمَّدُ بْنُ الْعَلاَءِ، عَنْ أَبِي مُعَاوِيَةَ، عَنِ الأَعْمَشِ، عَنْ شَقِيقٍ، عَنْ عَبْدِ اللَّهِ، قَالَ قِتَالُ الْمُؤْمِنِ كُفْرٌ وَسِبَابُهُ فُسُوقٌ ‏.‏

It was narrated that 'Abdullah said:"Fighting a believer is Kufr and defaming him is evildoing

Scholarly Authentication

The label above is the grade most of these scholars gave, each scholar counted once — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. When they judged only its chain of narrators (“Isnaad”), the label says “Sound chain”. Each scholar's own wording:

Al-AlbaniSahih Muquf
Zubair Ali ZaiHasan

Our source also lists this ruling under Abu Ghuddah, the editor of the printed edition it was taken from. It is al-Albani's ruling printed again, so it is counted once.

In-book reference: 37:148