When ʿAli killed the people of an-Nahrawan he said: Look for him. And they found him in a ditch lying beneath the slain. They brought him out and ‘Ali ؓ came to his companions and said: If you could exercise restraint, I would have told you what Allah promised on the lips of Muhammad to those who kill them. I said: Did you hear that from the Messenger of Allah ﷺ? He said: Yes, by the Lord of the Kaʿbah.  

الْتَمِسُوهُ فَوَجَدُوهُ فِي حُفْرَةٍ تَحْتَ الْقَتْلَى فَاسْتَخْرَجُوهُ وَأَقْبَلَ عَلِيٌّ عَلَى أَصْحَابِهِ فَقَالَ لَوْلَا أَنْ تَبْطَرُوا لَأَخْبَرْتُكُمْ مَا وَعَدَ اللهُ مَنْ يَقْتُلُ هَؤُلَاءِ عَلَى لِسَانِ مُحَمَّدٍ ﷺ قُلْتُ أَنْتَ سَمِعْتَهُ مِنْ رَسُولِ اللهِ ﷺ؟ قَالَ إِي وَرَبِّ الْكَعْبَةِ