Then David ran, and stood over the Philistine, and took his sword, and drew it out of the sheath of it, and killed him, and cut off his head therewith. When the Philistines saw that their champion was dead, they fled.
Now when Saul saw David go out against this fellow, he said to his captain Abner, Who is this young fellow? [Who is his dad?] And Abner said, [I don't know,] as thy soul live I can't tell you. And so the king says, Inquire and find out whose son he is. And so as David returned from the slaughter of the Philistine, Abner took him, and brought him before Saul with the head of the Philistine still in his hand ( 1 Samuel 17:55-57 ).