Contradiction with 1 Samuel 16:21
This verse suggests David was already well-known to Saul as he became his armor-bearer, yet 1 Samuel 17:56 implies Saul does not recognize him.
1 Samuel 16:21: And David came to Saul, and stood before him: and he loved him greatly; and he became his armourbearer.
Contradiction with 1 Samuel 17:15
This verse mentions David going back and forth to tend his father’s sheep, indicating ongoing duties that are not aligned with someone Saul doesn’t know, as 1 Samuel 17:56 suggests.
1 Samuel 17:15: But David went and returned from Saul to feed his father's sheep at Bethlehem.
Contradiction with 1 Samuel 17:55
This verse immediately prior implies Saul was unfamiliar with David, contradicting earlier interactions they had.
1 Samuel 17:55: 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.