فَرَدَدْنَاهُمْ بِطَعْنٍ كَمَا يَخْرُجُ مِنْ خُرْبَةِ الْمَزَادِ الْمَاءُ
Meaning: We repelled them by spearing, their blood issuing like water from a punctured skin.
Radadnāhum means “we pushed them back,” with defeat or forced retreat in view. Bi-ṭaʿn identifies the thrusts that caused it. Khurbat al-mazād is the opening in a large water-skin from which its contents escape.
The comparison is not about water’s beauty. It stresses sudden, forceful discharge. A familiar desert object makes the blood issuing from wounds vivid; the retreat is part of the wider narrated event.