Numbers 22:7, 17, 18

The elders of Moab and Midian left, taking with them the fee for divination. When they came to Balaam, they told him what Balak had said.

because I will reward you handsomely and do whatever you say. Come and put a curse on these people for me.”

But Balaam answered them, “Even if Balak gave me all the silver and gold in his palace, I could not do anything great or small to go beyond the command of the LORD my God.