King Saul asks who David's father was in 1 Samuel 17 for rhetorical effect in response to seeing how a young boy like David killed a giant, Goliath?

Question

There is confusion as to why King Saul asked who David's father was in 1 Samuel 17 because the preceding 1 Samuel 16 chapter already recounts the story of how King Saul came know and meet David.
However, Is it possible that King Saul merely asks who David's father was in 1 Samuel 17 for rhetorical effect in response to seeing how a young shepherd boy like David killed a giant named Goliath?

1 Samuel 16:17-22 New American Standard Bible 1995

17 So Saul said to his servants, “Provide for me now a man who can play well and bring him to me.” 18 Then one of the young men said, “Behold, I have seen a son of Jesse the Bethlehemite who is a skillful musician, a mighty man of valor, a warrior, one prudent in speech, and a handsome man; and the Lord is with him.” 19 So Saul sent messengers to Jesse and said, “Send me your son David who is with the flock.” 20 Jesse took a donkey loaded with bread and a jug of wine and a young goat, and sent them to Saul by David his son. 21 Then David came to Saul and [a]attended him; and [b]Saul loved him greatly, and he became his armor bearer. 22 Saul sent to Jesse, saying, “Let David now stand before me, for he has found favor in my sight.”

1 Samuel 17:55-58

New American Standard Bible 1995

55 Now when Saul saw 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.” 56 The king said, “You inquire whose son the youth is.” 57 So when David returned from killing the Philistine, Abner took him and brought him before Saul with the Philistine’s head in his hand. 58 Saul said to him, “Whose son are you, young man?” And David answered, “I am the son of your servant Jesse the Bethlehemite.”

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17:55-58 The Westminster Leningrad Codex

55 וְכִרְא֨וֹת שָׁא֜וּל אֶת־דָּוִ֗ד יֹצֵא֙ לִקְרַ֣את הַפְּלִשְׁתִּ֔י אָמַ֗ר אֶל־אַבְנֵר֙ שַׂ֣ר הַצָּבָ֔א בֶּן־מִי־זֶ֥ה הַנַּ֖עַר אַבְנֵ֑ר וַיֹּ֣אמֶר אַבְנֵ֔ר חֵֽי־נַפְשְׁךָ֥ הַמֶּ֖לֶךְ אִם־יָדָֽעְתִּי׃

56 וַיֹּ֖אמֶר הַמֶּ֑לֶךְ שְׁאַ֣ל אַתָּ֔ה בֶּן־מִי־זֶ֖ה הָעָֽלֶם׃ ס

57 וּכְשׁ֣וּב דָּוִ֗ד מֵֽהַכּוֹת֙ אֶת־הַפְּלִשְׁתִּ֔י וַיִּקַּ֤ח אֹתוֹ֙ אַבְנֵ֔ר וַיְבִאֵ֖הוּ לִפְנֵ֣י שָׁא֑וּל וְרֹ֥אשׁ הַפְּלִשְׁתִּ֖י בְּיָדֽוֹ׃

58 וַיֹּ֤אמֶר אֵלָיו֙ שָׁא֔וּל בֶּן־מִ֥י אַתָּ֖ה הַנָּ֑עַר וַיֹּ֣אמֶר דָּוִ֔ד בֶּֽן־עַבְדְּךָ֥ יִשַׁ֖י בֵּ֥ית הַלַּחְמִֽי׃

Answer 1

Is it possible that King Saul merely asks who David's father was in 1 Samuel 17 for rhetorical effect in response to seeing how a young shepherd boy like David killed a giant named Goliath?

Unlikely.

1 Samuel 17:

55 Now when Saul saw David going out against the Philistine, he said to Abner the commander of the army, “Abner, whose son is this young man?”

Saul probably had forgotten the name of David's father.

And Abner said, “By your life, O king, I do not know.”

Abner wasn't kidding. He didn't know either.

56 The king said, “You inquire whose son the youth is.”

The king insisted to find out. This command to Abner certainly wasn't rhetorical.

57 So when David returned from killing the Philistine, Abner took him and brought him before Saul with the Philistine’s head in his hand. 58 Saul said to him, “Whose son are you, young man?”

The question wasn't rhetorical. David certainty didn't take it that way.

And David answered, “I am the son of your servant Jesse the Bethlehemite.”

Is it possible that King Saul merely asks who David's father was in 1 Samuel 17 for rhetorical effect in response to seeing how a young shepherd boy like David killed a giant named Goliath?

It is more likely that King Saul didn't remember who David's father was. Now that David had killed Goliath, Saul really wanted to know.

Answer 2

Saul's royal court governed a country of many millions of people which would have required both a central and distributed bureaucracy or reasonable size. David, when he began his service as a court musician (1 Sam 16:19-23), would have been a very minor court official with the most perfunctory (brief with minimal details) introduction to Saul. This would have been made worse by Saul's rapidly developing mental illness.

In 1 Sam 17 we have a barely noticed court musician suddenly being revealed as a significant warrior with astonishing audacity. Correspondingly, Saul now needs to know MUCH more about this lad and his origin - I am sure that the conversation between David and Abner was much longer and more detailed than the single sentence recorded in 1 Sam 17:58, precisely as suggested in 1 Sam 18:1, 2.

After David had finished speaking with Saul, the souls of Jonathan and David were knit together, and Jonathan loved him as himself. And from that day Saul kept David with him and did not let him return to his father’s house.

This also suggests that David, up to this time, was only part-time in the royal court, but then became a full-time courtesan in the service of Saul.

It is also possible that Saul's mental illness contributed to his poor memory of the hitherto minor courtesan and wanted a fuller introduction to what would obviously be a very useful person to Saul.

Benson observes this:

1 Samuel 17:55. Whose son is this youth? — It may, at first sight, appear strange that Saul should be represented here as not knowing who David was, when we have a relation in the foregoing chapter of his sending for him to court, being highly pleased with his behaviour, and much delighted with his music, making him his armour-bearer, and sending to his father Jesse to ask his leave for his continuance at court. But it may be observed that Saul, in this place, does not express an entire ignorance of David, but only inquires whose son he was — A question of the more consequence to him, as he had promised his daughter in marriage to the conqueror of Goliath. Either Saul had never before made any inquiry about his parentage, or both he and Abner had forgotten whence he was. And this might very easily happen to a king and a general of an army, who daily see and have to do with so many different faces, and who pay so little regard to things of this sort. Nay, if Saul had entirely forgotten David, it would not have been strange, considering that he had been but little with him, had some time ago been dismissed from the court, and was returned home, where he had remained at least a year or two, during which time Saul had not seen him. Besides, the distemper of Saul’s mind might make him forgetful, and David might now be much changed, both in his countenance and in his habit. Abner said, I cannot tell — Abner’s employment was generally in the camp, when David was at the court; and when Abner was there he probably took little notice of a youth so much inferior to him as David was.

Answer 3

David's biological father may be indeed not Jesse as David himself states he was conceived in sin (out of wedlock?)

Behold, I was brought forth in iniquity, And in sin my mother conceived me. New King James Version PS51:5

Also he states that he were monogeneous (all genes from one parent only, and him being a male it has to be his father as only males have Y chromosome):

ῥῦσαι ἀπὸ ῥομφαίας τὴν ψυχήν μου, καὶ ἐκ χειρὸς κυνὸς τὴν μονογενῆ μου· Swete's Septuagint Ps22:20

Rescue from the the sword my soul and from the hand promiscuous my monogeneous [genome]

Here I could not find an adequate and relevant translation, so above translation into English is mine.

Who is then David's father, we should also ask?