Charles Ellicott Commentary Numbers 22:40

"And Balak sacrificed oxen and sheep, and sent to Balaam, and to the princes that were with him." — Numbers 22:40 (ASV)

And Balak offered ... — Better, and Balak slew (or, slaughtered in sacrifice) , etc. The word rendered offered does not necessarily denote anything more than to slay. It is very commonly used, however, to denote slaying in sacrifice; and it is most probable that Balak made a sacrificial feast, and sent portions of the flesh to Balaam and the princes who were with him. Kings often acted as priests in ancient times, as, e.g., Melchizedek. (Compare Rex Anius, rex idem hominum Phoebique sacerdos, Aeneid 3:80.)