Albert Barnes Commentary 1 Samuel 22:4

"And he brought them before the king of Moab: and they dwelt with him all the while that David was in the stronghold." — 1 Samuel 22:4 (ASV)

He brought them before ... - The Septuagint renders this as “he persuaded (the face of) the king.”

In the hold - This refers to where David was after he left the cave of Adullam, probably in the land of Moab.

The phrase “all the while” indicates that David stayed for a considerable time in Moab.