The Ammonites and Moabites rose up against the inhabitants of Mount Seir, devoting them to destruction. And when they had finished off the inhabitants of Seir, they helped to destroy one another.
KJV
For the children of Ammon and Moab stood up against the inhabitants of mount Seir, utterly to slay and destroy [them]: and when they had made an end of the inhabitants of Seir, every one helped to destroy another.
ASV
For the children of Ammon and Moab stood up against the inhabitants of mount Seir, utterly to slay and destroy them: and when they had made an end of the inhabitants of Seir, every one helped to destroy another.