Sunan an-Nasa'i 4120
سنن النسائي#4120Sahihأَخْبَرَنَا عَلِيُّ بْنُ مُحَمَّدِ بْنِ عَلِيٍّ الْمِصِّيصِيُّ، قَالَ حَدَّثَنَا خَلَفٌ، عَنْ زَائِدَةَ، عَنْ هِشَامٍ، عَنِ الْحَسَنِ، عَنْ أَبِي بَكْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " إِذَا تَوَاجَهَ الْمُسْلِمَانِ بِسَيْفَيْهِمَا كُلُّ وَاحِدٍ مِنْهُمَا يُرِيدُ قَتْلَ صَاحِبِهِ فَهُمَا فِي النَّارِ " . قِيلَ لَهُ يَا رَسُولَ اللَّهِ هَذَا الْقَاتِلُ فَمَا بَالُ الْمَقْتُولِ قَالَ " إِنَّهُ كَانَ حَرِيصًا عَلَى قَتْلِ صَاحِبِهِ " .
It was narrated from Abu Bakrah that :The Prophet [SAW] said: "If two Muslims confront each other with swords, each of them wanting to kill the other, they will both be in Hell." It was said to him: "O Messenger of Allah, (we understand about) the killer, but what about the one who is killed?" He said: "He was determined to kill his companion
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: 37:155