Albert Barnes Commentary 1 Kings 22:44

"And Jehoshaphat made peace with the king of Israel." — 1 Kings 22:44 (ASV)

This probably refers to an early period in Jehoshaphat’s reign—about his eighth or ninth year—when he closed the long series of wars between the two kingdoms with a formal peace, perhaps at once cemented by a marriage between Jehoram and Athaliah (see the note on 1 Kings 22:2).