2 Chronicles 18:28-32

28So [Ahab] the king of Israel and Jehoshaphat king of Judah went up against Ramoth-gilead.

29The king of Israel said to Jehoshaphat, “I will disguise myself and will go into battle, but you put on your [royal] robes.” So the king of Israel disguised himself, and they went into the battle.

30Now the king of Aram (Syria) had commanded the captains of his chariots, saying, “Do not fight with the small or the great, but only with the king of Israel.”

31So when the captains of the chariots saw Jehoshaphat [of Judah], they said, “It is the king of Israel!” So they turned to fight against him, but Jehoshaphat called out [for God’s help], and the Lord helped him; and God diverted them away from him.

32When the captains of the chariots saw that it was not the king of Israel, they turned back from pursuing him.