Nasai

Explanation:
➊:
"And whoever kills a believer intentionally, his recompense is Hell, wherein he will abide forever." (: al-Nisa 4:93).

➋:
Will the repentance of one who intentionally and unjustly kills a believer be accepted or not? There is a difference of opinion among the Companions (radi Allahu anhum) regarding this. Ibn Abbas (radi Allahu anhu) is of the view that his repentance will not be accepted. His evidence is this very verse, which according to him is the absolute final verse on the matter, and no verse has been revealed to abrogate it. However, the majority of the Companions and the Salaf are of the opinion that the implication of other verses of the Qur'an is that repentance is accepted for all sins. If the repentance of a polytheist is accepted, then why would the repentance of one who commits intentional murder not be accepted? However, it is the case that Allah will make the murdered person pleased (with the killer).

Benefits and Issues:

➊
In the question of the inquirer, there is an allusion to Allah’s statement:
﴿وَإِنّى لَغَفّارٌ‌ لِمَن تابَ وَءامَنَ وَعَمِلَ صـلِحًا ثُمَّ اهتَدى﴾ ()
“And indeed, I am surely Most Forgiving to whoever repents, believes, and does righteous deeds, then remains guided.” (Ta-Ha 20:82)

➋
In the answer of Abdullah ibn Abbas (radi Allahu anhu), there is an allusion to this blessed verse:
﴿وَمَن يَقتُل مُؤمِنًا مُتَعَمِّدًا فَجَزاؤُهُ جَهَنَّمُ خـلِدًا فيها وَغَضِبَ اللَّهُ عَلَيهِ وَلَعَنَهُ وَأَعَدَّ لَهُ عَذابًا عَظيمًا﴾ ()
“Whoever kills a believer intentionally, his recompense is Hell, wherein he will abide forever, and Allah’s wrath is upon him, and He has cursed him and prepared for him a great punishment.” (An-Nisa 4:93)

➌
Forgiveness for the sin of murder is possible in several ways:

(a)
By being killed in retribution (qisas), because the implementation of the prescribed punishment (hadd) results in the sin being forgiven. (Sunan Ibn Majah, Hudud, Hadith: 2603)

(b)
By the heirs of the murdered person pardoning (the killer), whether this pardon is given in exchange for blood money (diyah) or for the sake of Allah’s pleasure without compensation.

(c)
By sincerely repenting with a true heart (as will be mentioned in the next hadith).

4.
In the blessed verse, the original punishment for the crime of murder is mentioned.
If the murderer does not receive pardon, then he may receive this punishment.
Some scholars have interpreted this punishment as applying in the case where the murderer considers murder to be lawful (halal), because regarding the unlawful as lawful is disbelief (kufr), and the punishment for a disbeliever is eternal Hellfire.
Or, “abiding forever” may mean remaining in Hell for a very long period.
See: (Tafsir Ahsanul Bayan, Surah An-Nisa, Ayah: 93)

(1) The issue under discussion is whether the repentance (tawbah) of one who deliberately and unjustly kills a believer can be accepted. Ibn Abbas radi Allahu anhu does not hold this view, because a specific verse regarding this has been revealed in Surah al-Nisa: “And whoever kills a believer intentionally, his recompense is Hell, wherein he will abide forever. And Allah’s wrath is upon him, and His curse, and He has prepared for him a great punishment.” () The apparent wording of the verse supports the position of Ibn Abbas, and furthermore, this is the greatest of the rights of the servants (huquq al-‘ibad), so how can there be forgiveness without the consent of the murdered person? However, other scholars are of the opinion that his repentance is also accepted. Their evidence is from the verse in Surah al-Furqan: “Except for those who repent, believe, and do righteous deeds—for them Allah will replace their evil deeds with good ones. And Allah is ever Forgiving, Merciful.” () In the preceding verse, major sins are mentioned, and among them is murder. The position of Ibn Abbas is that this verse is about the disbelievers, i.e., whoever commits murder while in a state of disbelief, then repents and accepts Islam, then by the blessing of Islam his sins will be forgiven, including murder. However, if after having faith, he deliberately kills an innocent believer, then for him is the verse in Surah al-Nisa, in which there is no room for repentance. But Ibn Abbas radi Allahu anhu is alone in this matter. The majority of scholars accept repentance, because after all, this is a major sin, not disbelief, so it is forgivable. “And He forgives whatever is less than that for whom He wills.” () As for its being related to the rights of the servants, it is not far-fetched that Allah, if He wills to forgive someone, will make the murdered person pleased with him from Himself, for example: by sending him to Paradise by His grace and making him happy, so that he forgives, and so on.

(2) “Abrogated it”—by this verse is meant the verse in Surah al-Furqan in which repentance is mentioned. Its being abrogated is plausible because it is a Makkan verse, while the other verse in Surah al-Nisa is Madinan. However, in light of the above reconciliation, there is no need to call any verse abrogated. And Allah knows best. (Also see Hadith: 3989 and Hadith: 4013)

“This verse has been revealed by Allah, the Exalted.” That is, the verse from Surah An-Nisa in which the punishment of the murderer is stated as eternal Hell.