Ahab disguised himself for battle. What did he tell Jehoshaphat to wear?

Answer: His royal robes

Ahab said, 'I will disguise myself, but you wear your royal robes,' and the Aramean chariot commanders took Jehoshaphat for the king.

“And the king of Israel said to Jehoshaphat, “I will disguise myself and go into battle, but you wear your royal robes.” So the king of Israel disguised himself and went into battle.”— 1 Kings 22:30 (BSB)