1 Samuel 17:53-55

American Standard Version

⁵³ And the children of Israel returned from chasing after the Philistines, and they plundered their camp. ⁵⁴ And David took the head of the Philistine, and brought it to Jerusalem; but he put his armor in his tent.

⁵⁵ And when Saul saw David go forth against the Philistine, he said unto Abner, the captain of the host, Abner, whose son is this youth? And Abner said, As thy soul liveth, O king, I cannot tell.