Al-Adab Al-Mufrad
Al-Adab Al-Mufrad 431
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، قَالَ: حَدَّثَنَا شُعْبَةُ، عَنْ زُبَيْدٍ قَالَ: سَمِعْتُ أَبَا وَائِلٍ، عَنْ عَبْدِ اللهِ، عَنِ النَّبِيِّ صلى الله عليه وسلم: سِبَابُ الْمُسْلِمِ فُسُوقٌ، وَقِتَالُهُ كُفْرٌ.
Unreviewed translation. All hadiths in this collection are available in five languages. Titles and introductions may remain in Arabic.
Sulayman ibn Harb narrated to us: Shu‘ba narrated to us, from Zubayd, who said: I heard Abu Wa’il, from ‘Abd Allah, from the Prophet (may Allah bless him and grant him peace), who said: Reviling a Muslim is wicked conduct, and fighting him is disbelief.
Notes and open questions — unreviewed
The Arabic uses فسوق for sinful, defiantly disobedient conduct and kufr for disbelief; the translation retains the distinction.