1 Samuel 17:55-58

55And when Saul saw David go forth against the Philistine, he said to Abner, the captain of the host, Abner, whose son is this young man? And Abner said, As thy soul liveth, O king, I cannot tell. 56And the king said, Inquire thou whose son this youth is. 57And as David returned from the slaughter of the Philistine, Abner took him, and brought him before Saul with the head of the Philistine in his hand. 58And Saul said to him, Whose son art thou, young man? And David said, I am the son of thy servant Jesse the Beth-lehemite.