It is (offered) in the way of Allah. The Messenger of Allah (ﷺ) said: For this you will have seven hundred she-camels on the Day of Judgment all of which will be muzzled.
Sahih Muslim Book 33, Hadith 193
← Previous Hadith 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."

Sahih Muslim Book 33, Hadith 192 Next Hadith → A similar tradition has been narrated on the authority of al-A'mash.

Sahih Muslim Book 33, Hadith 194