2 Chronicles 20:1, 23

Now it happened after this that the Moabites and the Ammonites, together with some of the Meunites, came to make war against Jehoshaphat.

For the sons of Ammon and Moab [suspecting betrayal] rose up against the inhabitants of Mount Seir, completely destroying them; and when they had finished with the inhabitants of Seir, they helped to destroy one another.