1 Samuel 17:50-58

So David triumphed over the Philistine with a sling and a stone, and he struck down the Philistine and killed him; but there was no sword in David’s hand. So he ran and stood over the Philistine, grasped his sword and drew it out of its sheath and killed him, and cut off his head with it. When the Philistines saw that their [mighty] champion was dead, they fled. The men of Israel and Judah stood with a shout and pursued the Philistines as far as the entrance to the valley and the gates of Ekron. And the [fatally] wounded Philistines fell along the way to Shaaraim, even as far as Gath and Ekron. The sons of Israel returned from their pursuit of the Philistines and plundered their camp. Then David took the head of the Philistine and brought it to Jerusalem, but he put his weapons in his tent. When Saul saw David going out against the Philistine, he said to Abner the captain of the army, “Abner, whose son is this young man?” And Abner answered, “By your life, O king, I do not know.” The king said, “Ask whose son the young man is.” When David returned from killing [Goliath] the Philistine, Abner took him and brought him before Saul with the head of the Philistine in his hand. Saul asked him, “Whose son are you, young man?” And David answered, “I am the son of your servant Jesse of Bethlehem.”