الشَّاتِمَيْ عِرْضِي وَلَمْ أَشْتُمُهُمَا وَالنَّاذِرَيْنِ إِذَا لَمْ أَلْقَهُمَا دَمِي
Those two insulted my honour though I had not insulted them; they had vowed concerning my blood if they could not confront me.
The dual forms al-shātimay and al-nādhirayn qualify the two sons mentioned immediately before. ʿIrḍī means personal or family honour; damī, my blood or life. The verse supplies the speaker’s stated reason for the feud, not an ethical endorsement of vengeance.