2 Chronicles 18:3, 29-32

Ahab king of Israel said to Jehoshaphat king of Judah, “Will you go with me to [fight against] Ramoth-gilead?” He answered, “I am as you are, and my people as your people [your hopes and concerns are ours]; we will be with you in the battle.”

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