Sahih Muslim 2888
Sahih Muslim · Book 54: The Book of Tribulations and Portents of the Last Hour · If Two Muslims Confront One Another With Their Swords
Abu Bakra reported Allah's Messenger (ﷺ) as saying:
وَحَدَّثَنَا أَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ ، حَدَّثَنَا غُنْدَرٌ ، عَنْ شُعْبَةَ ، ح وَحَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى ، وَابْنُ بَشَّارٍ قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ ، حَدَّثَنَا شُعْبَةُ ، عَنْ مَنْصُورٍ ، عَنْ رِبْعِيِّ بْنِ حِرَاشٍ ، عَنْ أَبِي بَكْرَةَ ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " إِذَا الْمُسْلِمَانِ حَمَلَ أَحَدُهُمَا عَلَى أَخِيهِ السِّلاَحَ فَهُمَا فِي جُرُفِ جَهَنَّمَ فَإِذَا قَتَلَ أَحَدُهُمَا صَاحِبَهُ دَخَلاَهَا جَمِيعًا " .
When two Muslims (confront each other) and the one amongst them attacks his brother with a weapon, both of them are at the brink of Hell-Fire. And when one of them kills his companion, both of them get into Hell-Fire.