If I encountered a person amongst the infidels (in the battlefield) and he attacked me and struck me and cut off one of my hands with the sword. Then he (in order to protect himself from me) took shelter of a tree and said: I become Muslim for Allah's sake. Messenger of Allah, can I kill him after he had uttered this? The Messenger of Allah ﷺ said: Do not kill him. I (the narrator) said: Messenger of Allah, he cut off my hand and uttered this after amputating it; should I then kill him? The Messenger of Allah ﷺ said: Don't kill him, for I you kill him, verily he would be in a position where you had been before killing him and verily you would be in a position where he had been before uttering (kalima).  

أَنَّهُ أَخْبَرَهُ أَنَّهُ قَالَ يَا رَسُولَ اللَّهِ أَرَأَيْتَ إِنْ لَقِيتُ رَجُلاً مِنَ الْكُفَّارِ فَقَاتَلَنِي فَضَرَبَ إِحْدَى يَدَىَّ بِالسَّيْفِ فَقَطَعَهَا ثُمَّ لاَذَ مِنِّي بِشَجَرَةٍ فَقَالَ أَسْلَمْتُ لِلَّهِ أَفَأَقْتُلُهُ يَا رَسُولَ اللَّهِ بَعْدَ أَنْ قَالَهَا قَالَ رَسُولُ اللَّهِ ﷺ لاَ تَقْتُلْهُ قَالَ فَقُلْتُ يَا رَسُولَ اللَّهِ إِنَّهُ قَدْ قَطَعَ يَدِي ثُمَّ قَالَ ذَلِكَ بَعْدَ أَنْ قَطَعَهَا أَفَأَقْتُلُهُ قَالَ رَسُولُ اللَّهِ ﷺ لاَ تَقْتُلْهُ فَإِنْ قَتَلْتَهُ فَإِنَّهُ بِمَنْزِلَتِكَ قَبْلَ أَنْ تَقْتُلَهُ وَإِنَّكَ بِمَنْزِلَتِهِ قَبْلَ أَنْ يَقُولَ كَلِمَتَهُ الَّتِي قَالَ  

I embraced Islam for Allah's sake. and in the hadith narrated by Ma'mar the words are: I knelt down to kill him, that he said; There is no god but Allah.  

عَنِ الزُّهْرِيِّ بِهَذَا الإِسْنَادِ أَمَّا الأَوْزَاعِيُّ وَابْنُ جُرَيْجٍ فَفِي حَدِيثِهِمَا قَالَ أَسْلَمْتُ لِلَّهِ كَمَا قَالَ اللَّيْثُ فِي حَدِيثِهِ وَأَمَّا مَعْمَرٌ فَفِي حَدِيثِهِ فَلَمَّا أَهْوَيْتُ لأَقْتُلَهُ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ  

Messenger of Allah, here is a point: If I happened to encounter a person amongst the infidels (in the battle). Then he narrated a hadith similar to the one transmitted by Laith.  

أَخْبَرَهُ أَنَّ الْمِقْدَادَ بْنَ عَمْرِو بْنِ الأَسْوَدِ الْكِنْدِيَّ وَكَانَ حَلِيفًا لِبَنِي زُهْرَةَ وَكَانَ مِمَّنْ شَهِدَ بَدْرًا مَعَ رَسُولِ اللَّهِ ﷺ أَنَّهُ قَالَ يَا رَسُولَ اللَّهِ أَرَأَيْتَ إِنْ لَقِيتُ رَجُلاً مِنَ الْكُفَّارِ ثُمَّ ذَكَرَ بِمِثْلِ حَدِيثِ اللَّيْثِ  

There is no god but Allah, I attacked him with a spear. It once occurred to me and I talked about it to the Apostle ﷺ. The Messenger of Allah ﷺ said: Did he profess" There is no god but Allah," and even then you killed him? I said: Messenger of Allah, he made a profession of it out of the fear of the weapon. He (the Holy Prophet) observed: Did you tear his heart in order to find out whether it had professed or not? And he went on repeating it to me till I wished I had embraced Islam that day. Sa'd said: By Allah, I would never kill any Muslim so long as a person with a heavy belly, i. e., Usama, would not kill. Upon this a person remarked: Did Allah not say this: And fight them until there is no more mischief and religion is wholly for Allah? Sa'd said: We fought so that there should be no mischief, but you and your companions wish to fight so that there should be mischief.  

بَعَثَنَا رَسُولُ اللَّهِ ﷺ فِي سَرِيَّةٍ فَصَبَّحْنَا الْحُرَقَاتِ مِنْ جُهَيْنَةَ فَأَدْرَكْتُ رَجُلاً فَقَالَ لاَ إِلَهَ إِلاَّ اللَّهُ فَطَعَنْتُهُ فَوَقَعَ فِي نَفْسِي مِنْ ذَلِكَ فَذَكَرْتُهُ لِلنَّبِيِّ ﷺ فَقَالَ رَسُولُ اللَّهِ ﷺ أَقَالَ لاَ إِلَهَ إِلاَّ اللَّهُ وَقَتَلْتَهُ قَالَ قُلْتُ يَا رَسُولَ اللَّهِ إِنَّمَا قَالَهَا خَوْفًا مِنَ السِّلاَحِ قَالَ أَفَلاَ شَقَقْتَ عَنْ قَلْبِهِ حَتَّى تَعْلَمَ أَقَالَهَا أَمْ لاَ فَمَازَالَ يُكَرِّرُهَا عَلَىَّ حَتَّى تَمَنَّيْتُ أَنِّي أَسْلَمْتُ يَوْمَئِذٍ قَالَ فَقَالَ سَعْدٌ وَأَنَا وَاللَّهِ لاَ أَقْتُلُ مُسْلِمًا حَتَّى يَقْتُلَهُ ذُو الْبُطَيْنِ يَعْنِي أُسَامَةَ قَالَ قَالَ رَجُلٌ أَلَمْ يَقُلِ اللَّهُ { وَقَاتِلُوهُمْ حَتَّى لاَ تَكُونَ فِتْنَةٌ وَيَكُونَ الدِّينُ كُلُّهُ لِلَّهِ} فَقَالَ سَعْدٌ قَدْ قَاتَلْنَا حَتَّى لاَ تَكُونَ فِتْنَةٌ وَأَنْتَ وَأَصْحَابُكَ تُرِيدُونَ أَنْ تُقَاتِلُوا حَتَّى تَكُونَ فِتْنَةٌ  

The Messenger of Allah may peace be upon him) sent us to Huraqat, a tribe of Juhaina. We attacked that tribe early in the morning and defeated them and I and a man from the Ansar caught hold of a person (of the defeated tribe). When we overcame him, he said: There is no god but Allah. At that moment the Ansari spared him, but I attacked him with my spear and killed him. The news had already reached the Apostle (peace be upon him), so when we came back he (the Apostle) said to me: Usama, did you kill him after he had made the profession: There is no god but Allah? I said. Messenger of Allah, he did it only as a shelter. The Prophet observed: Did you kill him after he had made the profession that there is no god but Allah? He (the Holy Prophet) went on repeating this to me till I wished I had not embraced Islam before that day.  

بَعَثَنَا رَسُولُ اللَّهِ ﷺ إِلَى الْحُرَقَةِ مِنْ جُهَيْنَةَ فَصَبَّحْنَا الْقَوْمَ فَهَزَمْنَاهُمْ وَلَحِقْتُ أَنَا وَرَجُلٌ مِنَ الأَنْصَارِ رَجُلاً مِنْهُمْ فَلَمَّا غَشَيْنَاهُ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ فَكَفَّ عَنْهُ الأَنْصَارِيُّ وَطَعَنْتُهُ بِرُمْحِي حَتَّى قَتَلْتُهُ قَالَ فَلَمَّا قَدِمْنَا بَلَغَ ذَلِكَ النَّبِيَّ ﷺ فَقَالَ لِي يَا أُسَامَةُ أَقَتَلْتَهُ بَعْدَ مَا قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ قَالَ قُلْتُ يَا رَسُولَ اللَّهِ إِنَّمَا كَانَ مُتَعَوِّذًا قَالَ فَقَالَ أَقَتَلْتَهُ بَعْدَ مَا قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ قَالَ فَمَازَالَ يُكَرِّرُهَا عَلَىَّ حَتَّى تَمَنَّيْتُ أَنِّي لَمْ أَكُنْ أَسْلَمْتُ قَبْلَ ذَلِكَ الْيَوْمِ  

Gather some men of your family so that I should talk to them. He ('As'as) sent a messenger to them (to the members of his family). When they had assembled, Jundab came there with a yellow hooded cloak on him, He said: Talk what you were busy in talking. The talk went on by turns, till there came his (Jundab's) turn. He took off the hooded cloak from his head and said: I have come to you with no other intention but to narrate to you a hadith of your Apostle: Verily the Messenger of Allah ﷺ sent a squad of the Muslims to a tribe of the polytheists. Both the armies confronted one another. There was a man among the army of polytheists who (was so dashing that), whenever he intended to kill a man from among the Muslims, he killed him. Amongst the Muslims too was a man looking forward to (an opportunity of) his (the polytheist's) unmindfulness. He (the narrator) said: We talked that he was Usama b, Zaid. When he raised his sword, he (the soldier of the polytheists) uttered:" There is no god but Allah," but he (Usama b. Zaid) killed him. When the messenger of the glad tidings came to the Apostle ﷺ he asked him (about the events of the battle) and he informed him about the man (Usama) and what he had done He (the Prophet of Allah) called for him and asked him why he had killed him. He (Usama) said: Messenger of Allah, he struck the Muslims and killed such and such of them. And he even named some of them. (He continued): I attacked him and when he saw the sword he said: There is no god but Allah. The Messenger of Allah ﷺ said: Did you kill him? He (Usama) replied in the affirmative. He (the Holy Prophet) remarked: What would you do with:" There is no god but Allah," when he would come (before you) on the Day of Judgment? He (Usama) said: Messenger of Allah, beg pardon for me (from your Lord). He (the Holy Prophet) said: What would you do with:" There is no god but Allah" when he would come (before you) on the Day of Judgment? He (the Holy Prophet) added nothing to it but kept saying: What would you do with:" There is no god but Allah," when he would come (before you) on the Day of Judgment?  

اجْمَعْ لِي نَفَرًا مِنْ إِخْوَانِكَ حَتَّى أُحَدِّثَهُمْ فَبَعَثَ رَسُولاً إِلَيْهِمْ فَلَمَّا اجْتَمَعُوا جَاءَ جُنْدَبٌ وَعَلَيْهِ بُرْنُسٌ أَصْفَرُ فَقَالَ تَحَدَّثُوا بِمَا كُنْتُمْ تَحَدَّثُونَ بِهِ حَتَّى دَارَ الْحَدِيثُ فَلَمَّا دَارَ الْحَدِيثُ إِلَيْهِ حَسَرَ الْبُرْنُسَ عَنْ رَأْسِهِ فَقَالَ إِنِّي أَتَيْتُكُمْ وَلاَ أُرِيدُ أَنْ أُخْبِرَكُمْ عَنْ نَبِيِّكُمْ إِنَّ رَسُولَ اللَّهِ ﷺ بَعَثَ بَعْثًا مِنَ الْمُسْلِمِينَ إِلَى قَوْمٍ مِنَ الْمُشْرِكِينَ وَإِنَّهُمُ الْتَقَوْا فَكَانَ رَجُلٌ مِنَ الْمُشْرِكِينَ إِذَا شَاءَ أَنْ يَقْصِدَ إِلَى رَجُلٍ مِنَ الْمُسْلِمِينَ قَصَدَ لَهُ فَقَتَلَهُ وَإِنَّ رَجُلاً مِنَ الْمُسْلِمِينَ قَصَدَ غَفْلَتَهُ قَالَ وَكُنَّا نُحَدَّثُ أَنَّهُ أُسَامَةُ بْنُ زَيْدٍ فَلَمَّا رَفَعَ عَلَيْهِ السَّيْفَ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ فَقَتَلَهُ فَجَاءَ الْبَشِيرُ إِلَى النَّبِيِّ ﷺ فَسَأَلَهُ فَأَخْبَرَهُ حَتَّى أَخْبَرَهُ خَبَرَ الرَّجُلِ كَيْفَ صَنَعَ فَدَعَاهُ فَسَأَلَهُ فَقَالَ لِمَ قَتَلْتَهُ قَالَ يَا رَسُولَ اللَّهَ أَوْجَعَ فِي الْمُسْلِمِينَ وَقَتَلَ فُلاَنًا وَفُلاَنًا وَسَمَّى لَهُ نَفَرًا وَإِنِّي حَمَلْتُ عَلَيْهِ فَلَمَّا رَأَى السَّيْفَ قَالَ لاَ إِلَهَ إِلاَّ اللَّهُ قَالَ رَسُولُ اللَّهِ ﷺ أَقَتَلْتَهُ قَالَ نَعَمْ قَالَ فَكَيْفَ تَصْنَعُ بِلاَ إِلَهَ إِلاَّ اللَّهُ إِذَا جَاءَتْ يَوْمَ الْقِيَامَةِ قَالَ يَا رَسُولَ اللَّهِ اسْتَغْفِرْ لِي قَالَ وَكَيْفَ تَصْنَعُ بِلاَ إِلَهَ إِلاَّ اللَّهُ إِذَا جَاءَتْ يَوْمَ الْقِيَامَةِ قَالَ فَجَعَلَ لاَ يَزِيدُهُ عَلَى أَنْ يَقُولَ كَيْفَ تَصْنَعُ بِلاَ إِلَهَ إِلاَّ اللَّهُ إِذَا جَاءَتْ يَوْمَ الْقِيَامَةِ