2 Chronicles (Author Compiled by Isaiah and Ezra from records of Nathan, Gad, Iddo, Ahijah, Jehu and others.)
Chapter 20
23And 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.
Original from The Bible Foundation - bf.org. They claim public domain status for their original text.