Why didn’t Saul recognize David (1 Samuel 17:55, 58 in light of 1 Samuel 16:14–23)?
The seeming contradiction between 17:55–58 and 16:14–23 may be resolved by noting that prior to this time David was not a permanent resident at Saul’s court (see v. 15; 18:2), so that Saul’s knowledge of David and his family may have been minimal. Further, Saul may have been so incredulous at David’s courage that he was wondering if his family background and social standing might explain his extraordinary conduct.