You and I are as one. My troops are your troops and my horses are your horses - 1 Kings 22:4
There is a danger of entering into alliances with evil men who have no intent to keep the peace
Jehoshaphat marred his legacy into an ill-advised and miltary alliance with Ahab - the godless king of Israel - 2 Kings 22:43-44
This led to a stinging defeat for Jehoshaphat and Israel and strong rebuke from the prophet Jehu - 2 Chronicles 19:13
God spared him because he had otherwise served him faithfully
His error was the comprise and lack of wisdom in dealing with Ahab