Numbers 23:27-30

Then Balak said to Balaam, “Please come; I will take you to another place. Perhaps it will please God to let you curse them for me from there.” So Balak brought Balaam to the top of [Mount] Peor, that overlooks the wasteland. And Balaam said to Balak, “Build seven altars for me here, and prepare for me seven bulls and seven rams here.” Balak did just as Balaam had said, and offered a bull and a ram on each altar.