Muslim

Ahnaf bin Qais reported: I set out with the intention of helping this person (Hadrat 'Ali) that Abu Bakr (RA) met me. He said: Ahnaf, where do you intend to go? I said: I intend to help the cousin of Allah's Messenger (ﷺ) , viz. 'Ali. Thereupon he said to me: Ahnaf, go back, for I heard Allah's Messenger (ﷺ) as saying: When two Muslims confront one another with swords (in hands) both the slayer and the slain would be in Fire. He (Ahnaf) said: I said, or it was said: Allah's Messenger, it may be the case of one who kills. but what about the slain (why would he be put in Hell-Fire)? Thereupon he said: He also intended to kill his companion.

Ahnaf bin Qais reported on the authority of Abu Bakr (RA) 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.

This hadith has been narrated on the authority of Hammad through another chain of transmitters.

Abu Bakr (RA) reported Allah's Messenger (ﷺ) as saying: 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.

Abu Hurairah (RA) reported Allah's Messenger (ﷺ) many ahadith and one of them was this: The last Hour will not come until the two parties (of Muslims) confront each other and there is a large-scale massacre amongst them and the claim of both of them is the same.

Abu Hurairah (RA) reported Allah's Messenger (ﷺ) as saying: The last Hour will not come unless there is much bloodshed. They said: What is harj? Thereupon he said: Bloodshed. Bloodshed.