It was narrated from 'Abdullah bin Buraidah, from the father, that a man came to the Prophet and said:"This man killed my brother." He said: "Go and kill him as he killed your brother." The man said to him: "Fear Allah and let me go, for that will bring you a greater reward and will be better for you and your brother on the Day of Resurrection." So he let him go. The Prophet was told about that, so he asked him about it, and he told him what he had said. He said: "Pardoning him would be better for you than what he would have done for you on the Day of Resurrection when he said: 'O Lord, ask him why he killed me."'
أَخْبَرَنَا الْحَسَنُ بْنُ إِسْحَاقَ الْمَرْوَزِيُّ، قَالَ حَدَّثَنِي خَالِدُ بْنُ خِدَاشٍ، قَالَ حَدَّثَنَا حَاتِمُ بْنُ إِسْمَاعِيلَ، عَنْ بَشِيرِ بْنِ الْمُهَاجِرِ، عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ، عَنْ أَبِيهِ، أَنَّ رَجُلاً، جَاءَ إِلَى النَّبِيِّ صلى الله عليه وسلم فَقَالَ إِنَّ هَذَا الرَّجُلَ قَتَلَ أَخِي . قَالَ " اذْهَبْ فَاقْتُلْهُ كَمَا قَتَلَ أَخَاكَ " . فَقَالَ لَهُ الرَّجُلُ اتَّقِ اللَّهَ وَاعْفُ عَنِّي فَإِنَّهُ أَعْظَمُ لأَجْرِكَ وَخَيْرٌ لَكَ وَلأَخِيكَ يَوْمَ الْقِيَامَةِ . قَالَ فَخَلَّى عَنْهُ قَالَ فَأُخْبِرَ النَّبِيُّ صلى الله عليه وسلم فَسَأَلَهُ فَأَخْبَرَهُ بِمَا قَالَ لَهُ قَالَ فَأَعْنَفَهُ " أَمَا إِنَّهُ كَانَ خَيْرًا مِمَّا هُوَ صَانِعٌ بِكَ يَوْمَ الْقِيَامَةِ يَقُولُ يَا رَبِّ سَلْ هَذَا فِيمَ قَتَلَنِي " .
Nesai
The Book of Oaths (qasamah), Retaliation and Blood Money • Hadith 4731