Whether Allaah would forgive one who kills believer deliberately
3-9-2016 | IslamWeb
Question:
Assalaamu alaykum. Allaah says that He will forgive everyone but not the people who do Shirk (polytheism) so what about the below hadith that I am referring to. Does that contradict not contradict this? Allaah says that He will not forgive the one who does Shirk, but the hadith says, “Every sin is forgiven except a person who deliberately kills a Muslim or a person who dies as a non-Muslim (disbeliever).” What is that? The Prophet, sallallaahu 'alayhi wa sallam said, “Every sin is forgiven except a person who deliberately kills a Muslim or a person who dies as a non-Muslim (disbeliever).” [Abu Daawood]
Answer:
All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad 
is His slave and Messenger.
This hadeeth was reported by Abu Dawood, and a group of scholars, such as Ibn Hibbaan, Al-Haakim and Al-Albaani, classified it as saheeh (sound).
Ahlus-Sunnah wal-Jamaa’ah agreed that all sins – among which is killing a soul without right – with the exception of Shirk (associating partners with Allaah) are under the will of Allaah. If Allaah wills, He forgives the Muslim sinner, and if He wills, He punishes him, as Allaah says (what means): {Indeed, Allaah does not forgive association with Him, but He forgives what is less than that for whom He wills. And he who associates others with Allaah has certainly fabricated a tremendous sin.} [Quran 4:48]
As regards the difficulty of understanding this hadeeth, there are two answers: firstly, that this threat is in regard to the one who considers killing as lawful, and it is known that considering killing and similar absolutely prohibited acts as lawful is major disbelief that takes a person out of the fold of Islam according to the consensus of all the Muslims.
Secondly: that this threat does not literally apply to the killer but is just an exaggeration in order to repel him from doing so and to intimidate him.
Faydh al-Qadeer authored by Al-Munaawi reads:
“It is hoped that Allaah may forgive every sin with the exception of the one who dies while he is a Mushrik (someone who associates partners with Allaah), meaning that he disbelieves in Allaah. Shirk is specifically mentioned here because Shirk is the most common type of Kufr (disbelief) and not to exclude Kufr; or “killing a believer deliberately” without a right. Regarding non-forgiveness for associating partners with Allaah, this is an absolute ruling (that this sin is not forgiven). Allaah said (what means): {Indeed, Allaah does not forgive association with Him,}. Regarding killing, it is interpreted to mean that it is not forgiven if the killer considered killing as lawful, otherwise it is an exaggeration to repel him from killing and to intimidate him.”
For more benefit, please refer to fatwa 2608941.
Allaah knows best.