When Saul saw David go forth against the Philistine, he said to Abner, the captain of the host, Abner, whose son is this youth? Abner said, As your soul lives, O king, I can't tell.
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.