The word khulūd (Arabic: خلود) bears multiple meanings as per Al-Ma'ājim:
- Eternal with no start and no end, e.g., the existence of Allah (الدَّوَامُ وَالبَقَاءُ لِلَّهِ لاَ بِدَايَةَ لَهُ وَلاَ نِهَايَةَ).
- Eternal with a start and no end, e.g., the soul has a start but no end (خُلُود النَّفس: بقاؤها بعد فناء البدن مع الاحتفاظ بخصائصها ومميزاتها الفرديّة).
- Being in a place for a long time (خَلَدَ بِالْمَكَان ِ: أَقَامَ فِيهِ وَدَامَ وَاسْتَقَرَّ طَوِيلاً).
Allah ﷻ informs us that the only sin that is not forgivable is to attribute partners to Allah in worship. Any sins other than shirk may be forgiven by Allah ﷻ as He wills:
إِنَّ اللَّهَ لَا يَغْفِرُ أَن يُشْرَكَ بِهِ وَيَغْفِرُ مَا دُونَ ذَٰلِكَ لِمَن يَشَاءُ ۚ وَمَن يُشْرِكْ بِاللَّهِ فَقَدْ ضَلَّ ضَلَالًا بَعِيدًا
Verily! Allah forgives not (the sin of) setting up partners in worship with Him, but He forgives whom he pleases sins other than that, and whoever sets up partners in worship with Allah, has indeed strayed far away.
— Surat An-Nisa' 4:116
Killing a believer intentionally is bound to be one of two cases:
- While considering the act of murder to be permissible (halāl), or
- While considering the act of murder to be prohibited (harām).
Killing a believer (or disbelievers for that matter) while considering the act of murder as permissible is considered kufr, hence punishable by eternity in Hellfire with no chance of getting out unless Allah wills otherwise:
إِنَّ اللَّهَ لَعَنَ الْكَافِرِينَ وَأَعَدَّ لَهُمْ سَعِيرًا خَالِدِينَ فِيهَا أَبَدًا لَّا يَجِدُونَ وَلِيًّا وَلَا نَصِيرًا
Verily, Allah has cursed the disbelievers and has prepared for them a flaming Fire (Hell). Wherein they will abide forever, and they will find neither a Wali (a protector) nor a helper.
— Surat Al-Ahzab 33:64-65
Note the use of the word abada (Arabic: أَبدا) in connection with the word khālidīn (Arabic: خالدين); it shows that there is no end to their time in Hellfire (unless Allah wills otherwise).
If killing a believer is done while the murderer acknowledges that the act is harām, this is considered an act that constitutes a major sin but does not reach the level of kufr, hence the punishment may not be without end (the verse does not use the word abada):
وَمَن يَقْتُلْ مُؤْمِنًا مُّتَعَمِّدًا فَجَزَاؤُهُ جَهَنَّمُ خَالِدًا فِيهَا وَغَضِبَ اللَّهُ عَلَيْهِ وَلَعَنَهُ وَأَعَدَّ لَهُ عَذَابًا عَظِيمًا
And whoever kills a believer intentionally, his recompense is Hell to abide therein, and the Wrath and the Curse of Allah are upon him, and a great punishment is prepared for him.
— Surat An-Nisa' 4:93
'Abdul-'Aziz ar-Rajihi said that the use of the word khulūd in this verse refers to staying in Hellfire for a considerable amount of time. Whoever believes that there is no deity worthy of worship but Allah will eventually enter Jannah as the Prophet ﷺ said:
عَنْ قَتَادَةَ، حَدَّثَنَا أَنَسُ بْنُ مَالِكٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " يَخْرُجُ مِنَ النَّارِ مَنْ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ وَكَانَ فِي قَلْبِهِ مِنَ الْخَيْرِ مَا يَزِنُ شَعِيرَةً ثُمَّ يَخْرُجُ مِنَ النَّارِ مَنْ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ وَكَانَ فِي قَلْبِهِ مِنَ الْخَيْرِ مَا يَزِنُ بُرَّةً ثُمَّ يَخْرُجُ مِنَ النَّارِ مَنْ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ وَكَانَ فِي قَلْبِهِ مِنَ الْخَيْرِ مَا يَزِنُ ذَرَّةً " .
Anas b. Malik reported: Verily the Apostle (ﷺ) said: He who professed: There is no god but Allah, would be brought out of the Fire even though he has in his heart virtue equal to the weight of a barley grain. Then he who professed: There is no god but Allah, would come out of the Fire, even though he has in his heart virtue equal to the weight of a wheat grain. He would then bring out from the Fire he who professed: There is no god but Allah, even though he has in his heart virtue equal to the weight of an atom.
— Sahih Muslim, Book 1, Hadith 386
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