“Bela died, and Yovav, son of Zerah, of Botzra, reigned in his stead” (Genesis 36:33). “Bela died” (Genesis 36:33) – Rabbi Abahu said: This is analogous to a prince who was involved in litigation with someone and [the other litigant’s] sustenance ran out. Someone came and supplied him with sustenance. The king said: ‘I will contend only with the one who provided him with sustenance.’
So, the Holy One blessed be He said: ‘Kingdom had already been uprooted from Edom, and Botzra came and provided them with kings? That is why I will contend only with Botzra,’ as it is stated: “For there is a sacrifice to the Lord in Botzra…” (Isaiah 34:6). Rabbi Berekhya said: Nevertheless, “and a great slaughter in the land of Edom” (Isaiah 34:6).11Although God’s anger is directed primarily at Botzra, He also brings great slaughter to Edom.