Numbers 22:18-20, 35

Then 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 word of the LORD my God, to do less or more. Now therefore, please, you also 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 come to call you, rise and go with them; but only the word which I speak to you—that you shall do.”

Then the Angel of the LORD said to Balaam, “Go with the men, but only the word that I speak to you, that you shall speak.” So Balaam went with the princes of Balak.