David said, Yahweh who delivered me out of the paw of the lion, and out of the paw of the bear, he will deliver me out of the hand of this Philistine. Saul said to David, Go, and Yahweh shall be with you.
It was a trophy that David had, and he wasn't gonna let the thing go. He was gonna carry it around for a few days. Must have been a big head too, you know, the guy's nine foot, six inches tall.