He replied:

Praise be to Allah.

If he kills him because of his Islamic faith—as a Christian fights Muslims because of their religion—then he is an unbeliever worse than an unbeliever bound by a treaty. He is an unbeliever at war with the Muslims, like the unbelievers who fight the Prophet, may Allah bless him and grant him peace, and his Companions. Such people will remain in Hell forever, as will other unbelievers.

But if he kills him unlawfully out of enmity, over money, because of a dispute, or for a similar reason, this is a major sin. According to Ahl al-Sunnah wa-l-Jamāʿah, he is not deemed an unbeliever merely for that; it is the Kharijites who declare people unbelievers for such acts. According to Ahl al-Sunnah wa-l-Jamāʿah, no one who upholds Allah’s oneness will remain in the Fire forever, contrary to the Muʿtazilites, who maintain that sinful Muslims will remain there eternally.

They may cite as evidence the words of the Most High:

“Whoever kills a believer intentionally, his recompense is Hell, to remain there forever. Allah is angry with him, has cursed him, and has prepared for him a tremendous punishment.”

One response to them is that this refers to someone who deliberately kills a believer because of his faith. Most, however, have not interpreted the verse in this way. Rather, they have said: This is an unqualified threat of punishment, clarified by the words of the Most High:

“Indeed, Allah does not forgive associating partners with Him, but He forgives anything less than that for whomever He wills.”

In this connection, an account is related from a follower of the Sunnah who was at a gathering attended by ʿAmr ibn ʿUbayd, the leader of the Muʿtazilites. ʿAmr said, “I will be brought forth on the Day of Resurrection and asked, ‘ʿAmr, on what basis did you say that I would not forgive a killer?’ I will reply, ‘You, my Lord, said: “Whoever kills a believer intentionally, his recompense is Hell, to remain there forever.”’”

The narrator said: “I said to him, ‘What if He says to you: “But I also said: ‘Indeed, Allah does not forgive associating partners with Him, but He forgives anything less than that for whomever He wills.’ On what basis did you know that I would not will to forgive this person?”’”

ʿAmr ibn ʿUbayd fell silent.