The Book of Tribulations and Portents of the Last Hour
54/4. Chapter:
If Two Muslims Confront One Another With Their Swords
Sahih Muslim
وَحَدَّثَنَاهُ أَحْمَدُ بْنُ عَبْدَةَ الضَّبِّيُّ، حَدَّثَنَا حَمَّادٌ، عَنْ أَيُّوبَ، وَيُونُسَ، وَالْمُعَلَّى بْنِ زِيَادٍ، عَنِ الْحَسَنِ، عَنِ الأَحْنَفِ بْنِ قَيْسٍ، عَنْ أَبِي بَكْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا الْتَقَى الْمُسْلِمَانِ بِسَيْفَيْهِمَا فَالْقَاتِلُ وَالْمَقْتُولُ فِي النَّارِ " .
Ahnaf b. Qais reported on the authority of Abu Bakra that Allah's Messenger (ﷺ) said: When two Muslims confront each other with their swords, both the slayer and the slain are doomed to Hell-Fire.
Reference : Sahih Muslim 2888bIn-book reference : Book 54, Hadith 19USC-MSA web (English) reference : Book 41, Hadith 6899