Albert Barnes Commentary 1 Samuel 21:2

"And David said unto Ahimelech the priest, The king hath commanded me a business, and hath said unto me, Let no man know anything of the business whereabout I send thee, and what I have commanded thee: and I have appointed the young men to such and such a place." — 1 Samuel 21:2 (ASV)

A further instance of David’s unscrupulous inventiveness (Compare to 1 Samuel 20:6).