2 Kings 3:4-8

Now Mesha the king of Moab was a sheep breeder, and he used to make tribute payments to the king of Israel of a hundred thousand lambs, and the wool of a hundred thousand rams.

However, when King Ahab died, the king of Moab broke with the king of Israel.

So King Jehoram left Samaria for battle at that time and mustered all Israel.

Then he went and sent word to Jehoshaphat the king of Judah, saying, “The king of Moab has broken away from me. Will you go with me to fight against Moab?” And he said, “I will go up. Consider me yours, my people as your people, my horses as your horses.”

Then he said, “Which way shall we go up?” And he answered, “The way of the wilderness of Edom.”