Albert Barnes Commentary 1 Samuel 22:10

"And he inquired of Jehovah for him, and gave him victuals, and gave him the sword of Goliath the Philistine." — 1 Samuel 22:10 (ASV)

He inquired of the Lord ... - This was not true, but Ahimelech going to get the sword from behind the ephod might have given Doeg reason to believe that he had put on the ephod to inquire of the Lord for David.