Before any king reigned over - Israel - See Genesis 36:31; (note), etc., where the same verses occur, as I have supposed borrowed from this place; and see the notes there.
Bela the son of Beor - "Balaam the impious son of Beor, the same as Laban the Syrian, who formed a confederacy with the sons of Esau, to destroy Jacob and his children; and he studied to destroy them utterly. Afterwards he reigned in Sodom; and the name of his royal city was Dinhabah, because it was undeservedly given to him." - T.