NET

23 The Ammonites and Moabites attacked the men from Mount Seir and annihilated them. When they had finished off the men of Seir, they attacked and destroyed one another.

Darby

23 And the children of Ammon and Moab stood up against the inhabitants of mount Seir, to exterminate and destroy [them]; and when they had made an end of the inhabitants of Seir, they helped to destroy one another.

KJV

23 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.