Sahih Muslim | Book 20 | Chapter 36

Narrated by It has been narrated on the authority of Abu Huraira that the Messenger Allah (may peace be upon him)
It has been narrated on the authority of Abu Huraira that the Messenger Allah (may peace be upon him) said: A disbeliever and a believer who killed him will never be gathered together in Hell.

Narrated by It has been narrated on the authority of Abu Huraira that the Messenger of Allah (may peace be upon him)
It has been narrated on the authority of Abu Huraira that the Messenger of Allah (may peace be upon him) said: No two such persons shall be together in Hell as if one of them is such that his presence hurts the other. It was asked: Messenger of Allah, who are they? He said: A believer who killed a disbeliever and (then) kept to the right path.