1 Samuel 17:55-59

Now when Saul had seen David going out against the Philistine, he said to Abner the commander of the army, “Abner, whose son is this young man?” And Abner said, “By your life, O king, I do not know.”

And the king said, “You then, ask whose son the youth is.”

So when David returned from killing the Philistine, Abner took him and brought him before Saul with the Philistine’s head in his hand.

Then Saul said to him, “Whose son are you, young man?” And David answered, “I am the son of your servant Jesse the Bethlehemite.”