Numbers 23:27-31

Then Balak said to Balaam, “Please come, I will take you to another place; perhaps it will be agreeable with God that you curse them for me from there.”

So Balak took Balaam to the top of Peor, which overlooks the desert.

And Balaam said to Balak, “Build seven altars for me here and prepare seven bulls and seven rams for me here.”

Balak did just as Balaam had said, and offered up a bull and a ram on each altar.