Matthew Poole and continuators on Numbers 31:8

8 And they slew the Kings of Midian , besides the rest of them that were slain; namely, Evi, and Rekem, and Zur , and Hur, and Reba, five Kings of Midian: Balaam also the son of Beor, they slew with the sword.

Called Dukes or Princes of Sihon, Ios. 13. 21. because they were subject to him while he lived, but upon his death they resumed their Kingly power.

The Father of Cozbi, Numb. 25. 15.

Obj. he was gone and returned to his own place, Numb. 24. 25. which was Aram or Mesopotamia, Numb. 23. 7. Answ. Either he did go thitherward, but in his journey made some stay in Midian, where he was overtaken by divinevengeance: or understanding the success of his wicked counsel left with Balaam in the sin and slaughter of the Israelites, he returned partly to enjoy the reputation and reward of his counsel which he had lost before, and partly to employ his Hellish arts against Israel, now they were, as he thought forsaken by their God, and exposed to his malice. Here Balaam dies the death of the wicked, and not of the righteous, as he desired, Numb. 23. 10.

Marginal references: Josh. 13. 21.