I asked Ibn 'Abbas (about the verse relating to intentional homicide in Surat An-Nisa') He said: When the verse "Those who invoke not with Allah any other god, nor slay such life as Allah had made sacred, except for just cause" was revealed, the polytheists of Mecca said: We have killed the soul prohibited by Allah, invoked another god along with Allah for worship, and committed shameful deeds. So Allah revealed the verse "unless he repents, believes, and works righteous deeds, for Allah will change the evil of such persons into good." This is meant for them. As regards the verse "if a man kills a believer intentionally, his recompense is Hell" He said: If a man knows the command of Islam and intentionally kills a believer, his repentance wil not be accepted. I then mentioned it to Mujahid. He said: "Except the one who is ashamed (of his sin)."  

لَمَّا نَزَلَتِ الَّتِي فِي الْفُرْقَانِ { وَالَّذِينَ لاَ يَدْعُونَ مَعَ اللَّهِ إِلَهًا آخَرَ وَلاَ يَقْتُلُونَ النَّفْسَ الَّتِي حَرَّمَ اللَّهُ إِلاَّ بِالْحَقِّ } قَالَ مُشْرِكُو أَهْلِ مَكَّةَ قَدْ قَتَلْنَا النَّفْسَ الَّتِي حَرَّمَ اللَّهُ وَدَعَوْنَا مَعَ اللَّهِ إِلَهًا آخَرَ وَأَتَيْنَا الْفَوَاحِشَ فَأَنْزَلَ اللَّهُ { إِلاَّ مَنْ تَابَ وَآمَنَ وَعَمِلَ عَمَلاً صَالِحًا فَأُولَئِكَ يُبَدِّلُ اللَّهُ سَيِّئَاتِهِمْ حَسَنَاتٍ } فَهَذِهِ لأُولَئِكَ قَالَ وَأَمَّا الَّتِي فِي النِّسَاءِ { وَمَنْ يَقْتُلْ مُؤْمِنًا مُتَعَمِّدًا فَجَزَاؤُهُ جَهَنَّمُ } الآيَةُ قَالَ الرَّجُلُ إِذَا عَرَفَ شَرَائِعَ الإِسْلاَمِ ثُمَّ قَتَلَ مُؤْمِنًا مُتَعَمِّدًا فَجَزَاؤُهُ جَهَنَّمُ لاَ تَوْبَةَ لَهُ فَذَكَرْتُ هَذَا لِمُجَاهِدٍ فَقَالَ إِلاَّ مَنْ نَدِمَ  

[Machine] Regarding these two verses, their command is concerning those in Surah Al-Furqan who do not invoke any deity besides Allah and do not kill a soul which Allah has forbidden except for a just cause, and also in Surah An-Nisa, "And whoever kills a believer intentionally, his recompense is Hell." I asked Ibn Abbas about this, and he said, "When the verse in Surah Al-Furqan was revealed, the polytheists of Makkah said, 'We have killed the soul which Allah has forbidden, and we have associated partners with Allah, and we have committed indecent actions.' Then the verse was revealed, 'Except for those who repent, believe, and do righteous deeds.'" And he said, "This is referring to those people." As for the verse in Surah An-Nisa, "And whoever kills a believer intentionally," it refers to a man who embraced Islam, performed the deeds of Islam, and then intentionally killed a believer. His recompense is Hell, and there is no repentance for him. I mentioned this to Mujahid, and he said, "It is correct according to the condition of the two sheikhs (referring to Bukhari and Muslim), as long as he has not been expelled." (According to the condition of Bukhari and Muslim)  

عَنْ هَاتَيْنِ الْآيَتَيْنِ مَا أَمْرُهُمَا الَّتِي فِي سُورَةِ الْفُرْقَانِ {وَالَّذِينَ لَا يَدْعُونَ مَعَ اللَّهِ إِلَهًا آخَرَ وَلَا يَقْتُلُونَ النَّفْسَ الَّتِي حَرَّمَ اللَّهُ إِلَّا بِالْحَقِّ} [الفرقان 68] وَالَّتِي فِي سُورَةِ النِّسَاءِ {وَمَنْ يَقْتُلْ مُؤْمِنًا مُتَعَمِّدًا فَجَزَاؤُهُ جَهَنَّمَ} [النساء 93] الْآيَةُ قَالَ فَسَأَلْتُ ابْنَ عَبَّاسٍ عَنْ ذَلِكَ قَالَ «لَمَّا أَنْزَلَ الَّتِي فِي سُورَةِ الْفُرْقَانِ قَالَ مُشْرِكُوا أَهْلِ مَكَّةَ قَدْ قَتَلْنَا النَّفْسَ الَّتِي حَرَّمَ اللَّهُ بِغَيْرِ الْحَقِّ وَدَعَوْنَا مَعَ اللَّهِ إِلَهًا آخَرَ وَأَتَيْنَا الْفَوَاحِشَ» قَالَ فَنَزَلَتْ {إِلَّا مَنْ تَابَ وَآمَنَ وَعَمِلَ عَمَلًا صَالِحًا} [الفرقان 70] الْآيَةَ قَالَ «فَهَؤُلَاءِ لِأُولَئِكَ» قَالَ وَأَمَّا الَّتِي فِي سُورَةِ النِّسَاءِ {وَمَنْ يَقْتُلْ مُؤْمِنًا مُتَعَمِّدًا} [النساء 93] الْآيَةُ فَهُوَ الرَّجُلُ الَّذِي قَدْ عَرَفَ الْإِسْلَامَ وَعَمِلَ عَمَلَ الْإِسْلَامِ ثُمَّ قَتَلَ مُؤْمِنًا مُتَعَمِّدًا فَجَزَاؤُهُ جَهَنَّمَ لَا تَوْبَةَ لَهُ قَالَ فَذَكَرْتُ ذَلِكَ لِمُجَاهِدٍ فَقَالَ إِلَّا مَنْ نَدِمَ «صَحِيحٌ عَلَى شَرْطِ الشَّيْخَيْنِ وَلَمْ يُخْرِجَاهُ» على شرط البخاري ومسلم