1 Samuel 17:55

And when Saul saw David go forth against the Philistine,.... Set out to meet him, and engage with him, as he might from the side of the mountain, where he was encamped:

he said unto Abner, the captain of the host; his own cousin, whom he had raised to this high post in the army, 1 Samuel 14:50;

Abner, whose son [is] this youth? it is thought strange by many that Saul should not know who he was, when he had been often at his court, and served him as a musician, and had been very useful to him, and he loved him, and made him his armourbearer, and even had just now conversed with him about encountering with the Philistine, and had clothed him with his own armour: to get rid of the former part of the objection, some have supposed that this event happened before David was his musician and armourbearer, and is by anticipation spoken of in

1 Samuel 16:14, but that the connection with this and the following chapter will not admit of; and besides, before this event, David is said to return home from Saul, 1 Samuel 17:15; so that it is certain he had been at Saul's court, and in his presence before: but to remove this seeming difficulty it may be observed, that Saul, having laboured under a disorder of body and mind, might easily forget David, and his serving him in the above capacity; and to which the multiplicity of business, and of persons in a court, might greatly contribute; and what with the distance of time, and the different habits in which David appeared, sometimes as a musician, and sometimes as a shepherd, and at other times as a soldier, and always as a servant, it is no wonder the king should not know him again; though after all it is not about his person that he inquires, but whose son he was, what was his father's name, and from what family he sprung; for though Saul was made acquainted with this in the time of his disorder, and therefore sent to his father Jesse for him, and afterwards desired leave for his continuance; yet this might slip out of his memory in a course of time, he having had no personal knowledge of Jesse, nor any correspondence with him, but just at that time; and it behoved him to know the pedigree of David, since, if he was victorious, he was not only to be enriched by him, but to have his daughter for wife, and his family ennobled:

and Abner said, [as] thy soul liveth, O king, I cannot tell; he swore by the life of Saul, as Joseph by the life of Pharaoh, that he knew nothing of him; which need not at all seem strange, that a general of an army, always employed in military affairs, and often abroad, should know nothing of a domestic servant of Saul's, under the character of a musician, and not always at court either; and still less that he should be ignorant of his family, and know nothing of his father, who lived in obscurity in Bethlehem, and was an old man in those days.