Numbers 22:18-20, 35

But Balaam answered and said to the servants of Balak, “Though Balak were to give me his house full of silver and gold, I could not go beyond the command of the LORD my God to do less or more. So you, too, please stay here tonight, that I may know what more the LORD will say to me.” And God came to Balaam at night and said to him, “If the men have come to call you, rise, go with them; but only do what I tell you.”

And the angel of the LORD said to Balaam, “Go with the men, but speak only the word that I tell you.” So Balaam went on with the princes of Balak.