Abu Bakra reported,

The Messenger of Allah ﷺ said, "When two Muslims confront each other with their swords, each intending to kill the other, and one of them kills his companion, both of them are in the Fire."Someone asked, "Messenger of Allah, this is understandable for the killer, but what about the one who was killed?"He replied, "Because he too intended to kill his companion."

Ahmad 20518

Sahih

حدثنا هاشم حدثنا المبارك عن الحسن

عن أبي بكرة قال

قال رسول الله ﷺ إذا تواجه المسلمان بسيفيهما وكلاهما يريد أن يقتل صاحبه فقتل أحدهما الآخر فهما في النار قيل يا رسول الله هذا القاتل فما بال المقتول قال لأنه أراد قتل صاحبه

أحمد 20518صحيح
Contents
Reference
Commentary
Ayat
Collection
Musnad Ahmad
Book
Abu Bakra Nufay bin Harith Thaqafi
Numbering
Darussalam 20518
Ahmad 20518