For thus do we find, that these nations resorted to divination, viz. (Devarim 18:14) "For these nations that you are to inherit resort to soothsayers and diviners, etc.", and (Numbers 22:7) "And the elders of Moav and the elders of Midian went, with (instruments of) divination in their hands," and (Joshua 13:22) "And Bilaam the son of Beor the augur they slew by the sword," and the elders of Midian divined and turned back.
The Mekhilta Observes That the Nations Surrounding Israel Relied on
Mekhilta Tractate Vayehi Beshalach 3:2