2 Chronicles 18:3, 29-32

And Ahab king of Israel said unto Jehoshaphat king of Judah, Wilt thou go with me to Ramoth-gilead? And he answered him, I am as thou art, and my people as thy people; and we will be with thee in the war.

And the king of Israel said unto Jehoshaphat, I will disguise myself, and go into the battle; but put thou on thy robes. So the king of Israel disguised himself; and they went into the battle. Now the king of Syria had commanded the captains of his chariots, saying, Fight neither with small nor great, save only with the king of Israel. And it came to pass, when the captains of the chariots saw Jehoshaphat, that they said, It is the king of Israel. Therefore they turned about to fight against him: but Jehoshaphat cried out, and Jehovah helped him; and God moved them to depart from him. And it came to pass, when the captains of the chariots saw that it was not the king of Israel, that they turned back from pursuing him.