Do not kill him, for if you kill him, he will be in the same position as yours before you kill him, and you will be in the same position as his before saying the word that he said

عَنْ المِقْدَادِ بْنَ عَمْرٍو الكِنْدِيَّ رضي الله عنه: أَنَّهُ قَالَ لِرَسُولِ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: أَرَأَيْتَ إِنْ لَقِيتُ رَجُلًا مِنَ الكُفَّارِ فَاقْتَتَلْنَا، فَضَرَبَ إِحْدَى يَدَيَّ بِالسَّيْفِ فَقَطَعَهَا، ثُمَّ لاَذَ مِنِّي بِشَجَرَةٍ، فَقَالَ: أَسْلَمْتُ لِلَّهِ، أَأَقْتُلُهُ يَا رَسُولَ اللَّهِ بَعْدَ أَنْ قَالَهَا؟ فَقَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «لاَ تَقْتُلْهُ» فَقَالَ: يَا رَسُولَ اللَّهِ إِنَّهُ قَطَعَ إِحْدَى يَدَيَّ، ثُمَّ قَالَ ذَلِكَ بَعْدَ مَا قَطَعَهَا؟ فَقَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ: «لاَ تَقْتُلْهُ، فَإِنْ قَتَلْتَهُ فَإِنَّهُ بِمَنْزِلَتِكَ قَبْلَ أَنْ تَقْتُلَهُ، وَإِنَّكَ بِمَنْزِلَتِهِ قَبْلَ أَنْ يَقُولَ كَلِمَتَهُ الَّتِي قَالَ».

Al-Miqdād ibn ‘Amr al-Kindi (may Allah be pleased with him) reported: He said to the Messenger of Allah (may Allah's peace and blessings be upon him): What if I meet a man from the disbelievers and we both fight? He strikes one of my hands with the sword and cuts it off, then he seeks refuge from me in a tree and says: I have submitted to Allah. O Messenger of Allah, should I kill him after saying it? The Messenger of Allah (may Allah's peace and blessings be upon him) said: "Do not kill him." He said: O Messenger of Allah, he cut off one of my hands, then he said this after cutting it off. The Messenger of Allah (may Allah's peace and blessings be upon him) said: "Do not kill him, for if you kill him, he will be in the same position as yours before you kill him, and you will be in the same position as his before saying the word that he said."

Source · Agreed upon

From the Hadith Encyclopedia (hadeethenc.com).