Sunan Abi Dawud 4877
سنن أبي داود#4877Da'ifحَدَّثَنَا جَعْفَرُ بْنُ مُسَافِرٍ، حَدَّثَنَا عَمْرُو بْنُ أَبِي سَلَمَةَ، قَالَ حَدَّثَنَا زُهَيْرٌ، عَنِ الْعَلاَءِ بْنِ عَبْدِ الرَّحْمَنِ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ مِنْ أَكْبَرِ الْكَبَائِرِ اسْتِطَالَةَ الْمَرْءِ فِي عِرْضِ رَجُلٍ مُسْلِمٍ بِغَيْرِ حَقٍّ وَمِنَ الْكَبَائِرِ السَّبَّتَانِ بِالسَّبَّةِ " .
Narrated AbuHurayrah: The Prophet (ﷺ) said: The gravest sin is going to lengths in talking unjustly against a Muslim's honour, and it is a major sin to abuse twice for abusing once
Scholarly Authentication
The label above is the grade most of these scholars gave — 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. Each scholar's own wording:
In-book reference: 43:105