مَا زِلْتُ أَرْمِيهِمْ بِثُغْرَةِ نَحْرِهِ وَلَبَانِهِ حَتَّى تَسَرْبَلَ بِالدَّمِ
I kept driving the front of the horse’s throat and chest against them until it appeared clothed in blood.
Mā ziltu conveys sustained action and ḥattā introduces the outcome. Tasarbala bi-l-dam makes blood into a garment: an image of extensive wounding, not literal clothing. The wounded horse exposes the cost of the heroic performance.