The Prophet [SAW] said: "If two Muslims confront each other with swords, and one kills the other, they will both be in Hell." It was said: "O Messenger of Allah, (we understand about) the killer, but what about the one who is killed?" He said: "He wanted to kill his companion." (Using translation from Nasāʾī 4118)
عَنِ النَّبِيِّ ﷺ إِذَا تَوَجَّهَ الْمُسْلِمَانِ بِسَيْفَيْهِمَا فَقَتَلَ أَحَدُهُمَا صَاحِبَهُ فَهُمَا فِي النَّارِ قِيلَ يَا رَسُولَ اللهِ هَذَا الْقَاتِلُ فَمَا بَالُ الْمَقْتُولِ؟ قَالَ إِنَّهُ أَرَادَ قَتْلَ صَاحِبِهِ