The Messenger of Allah ﷺ said, "Allah welcomes two men with a smile; one of whom kills the other and both of them enter Paradise. One fights in Allah's Cause and gets killed. Later on Allah forgives the 'killer who also get martyred (In Allah's Cause)."

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ: «يَضْحَكُ اللَّهُ إِلَى رَجُلَيْنِ يَقْتُلُ أَحَدُهُمَا الآخَرَ يَدْخُلاَنِ الْجَنَّةَ: يُقَاتِلُ هَذَا فِي سَبِيلِ اللَّهِ فَيُقْتَلُ، ثُمَّ يَتُوبُ اللَّهُ عَلَى الْقَاتِلِ فَيُسْتَشْهَدُ».

I went to support this man, and Abu Bakrah met me and said: Where are you going? I said, To help this man. He said: Go back, for I heard the Messenger of Allah ﷺ say: "If two Muslims meet each other with their swords, then both the killer and the one killed are in the Fire." I said: O Messenger of Allah, this is ˹for˺ the killer, so what about the ˹end of the˺ one killed? He said, “He was eager to kill his companion.”

ذَهَبْتُ لأَنْصُرَ هَذَا الرَّجُلَ فَلَقِيَنِي أَبُو بَكْرَةَ، فَقَالَ: أَيْنَ تُرِيدُ؟ قُلْتُ: أَنْصُرُ هَذَا الرَّجُلَ۔ قَالَ: ارْجِعْ، فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ: «إِذَا الْتَقَى الْمُسْلِمَانِ بِسَيْفَيْهِمَا فَالْقَاتِلُ وَالْمَقْتُولُ فِي النَّارِ۔» فَقُلْتُ: يَا رَسُولَ اللَّهِ، هَذَا الْقَاتِلُ، فَمَا بَالُ الْمَقْتُولِ؟ قَالَ: «إِنَّهُ كَانَ حَرِيصًا عَلَى قَتْلِ صَاحِبِهِ».

The Prophet of Allah ﷺ said: “Among those who came before you there was a man who killed ninety-nine people. He asked about the most knowledgeable person on earth, and he was directed to a monk. He went to him and said that he had killed ninety-nine people—was there any repentance for him? He said, ‘No,’ so he killed him, thereby completing one hundred. Then he asked about the most knowledgeable person on earth, and he was directed to a learned man. He said that he had killed one hundred people—was there any repentance for him? He said, ‘Yes—and who could stand between him and repentance? Go to such-and-such a land, for there are people there who worship Allah; worship Allah with them, and do not return to your land, for it is an evil land.’"

“So he set out, and when he had reached halfway along the road, death came to him. The angels of mercy and the angels of punishment disputed concerning him. The angels of mercy said, ‘He came repentant, turning with his heart toward Allah.’ The angels of punishment said, ‘He has never done any good at all.’ Then an angel came to them in the form of a human being, and they made him judge between them. He said, ‘Measure the distance between the two lands; whichever of them he is closer to, he belongs to it.’ So they measured, and found him closer to the land he had intended, and the angels of mercy took him.”

أَنَّ نَبِيَّ اللَّهِ ﷺ قَالَ: «كَانَ فِيمَنْ كَانَ قَبْلَكُمْ رَجُلٌ قَتَلَ تِسْعَةً وَتِسْعِينَ نَفْسًا۔ فَسَأَلَ عَنْ أَعْلَمِ أَهْلِ الأَرْضِ، فَدُلَّ عَلَى رَاهِبٍ۔ فَأَتَاهُ فَقَالَ إِنَّهُ قَتَلَ تِسْعَةً وَتِسْعِينَ نَفْسًا فَهَلْ لَهُ مِنَ تَوْبَةٍ۔ فَقَالَ لاَ، فَقَتَلَهُ فَكَمَّلَ بِهِ مِائَةً۔ ثُمَّ سَأَلَ عَنْ أَعْلَمِ أَهْلِ الأَرْضِ، فَدُلَّ عَلَى رَجُلٍ عَالِمٍ۔ فَقَالَ إِنَّهُ قَتَلَ مِائَةَ نَفْسٍ فَهَلْ لَهُ مِنْ تَوْبَةٍ۔ فَقَالَ نَعَمْ وَمَنْ يَحُولُ بَيْنَهُ وَبَيْنَ التَّوْبَةِ؟ انْطَلِقْ إِلَى أَرْضِ كَذَا وَكَذَا فَإِنَّ بِهَا أُنَاسًا يَعْبُدُونَ اللَّهَ، فَاعْبُدِ اللَّهَ مَعَهُمْ وَلاَ تَرْجِعْ إِلَى أَرْضِكَ فَإِنَّهَا أَرْضُ سَوْءٍ»،

«فَانْطَلَقَ حَتَّى إِذَا نَصَفَ الطَّرِيقَ أَتَاهُ الْمَوْتُ، فَاخْتَصَمَتْ فِيهِ مَلاَئِكَةُ الرَّحْمَةِ وَمَلاَئِكَةُ الْعَذَابِ۔ فَقَالَتْ مَلاَئِكَةُ الرَّحْمَةِ: جَاءَ تَائِبًا مُقْبِلاً بِقَلْبِهِ إِلَى اللَّهِ۔ وَقَالَتْ مَلاَئِكَةُ الْعَذَابِ: إِنَّهُ لَمْ يَعْمَلْ خَيْرًا قَطُّ۔ فَأَتَاهُمْ مَلَكٌ فِي صُورَةِ آدَمِيٍّ فَجَعَلُوهُ بَيْنَهُمْ۔ فَقَالَ: قِيسُوا مَا بَيْنَ الأَرْضَيْنِ فَإِلَى أَيَّتِهِمَا كَانَ أَدْنَى فَهُوَ لَهُ۔ فَقَاسُوهُ فَوَجَدُوهُ أَدْنَى إِلَى الأَرْضِ الَّتِي أَرَادَ، فَقَبَضَتْهُ مَلاَئِكَةُ الرَّحْمَةِ».