1 Samuel 17:55

Now when Saul saw David going out to meet the Philistine, he said to Abner, the commander of the army, "Whose son [is] this young man, Abner?" And Abner said, "As your soul lives, O king, I do not know."

1 Samuel 16:21-22

So David came to Saul and {entered his service}. He loved him greatly and {he became Saul's armor bearer}.

1 Samuel 17:58

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

Treasury of Scripture Knowledge

Summary

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.

Bible References

Whose son

1 Samuel 17:58
Then Saul said to him, "Whose son are you, young man?" And David said, "[I am] the son of your servant Jesse the Bethlehemite."
1 Samuel 16:21
So David came to Saul and {entered his service}. He loved him greatly and {he became Saul's armor bearer}.