Numbers 22:18-22

But Balaam replied to the servants of Balak, “Even if Balak were to give me his house full of silver and gold, I could not do anything, either small or great, contrary to the command of the Lord my God.

Now please, you also stay here tonight, and I will find out what else 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 and go with them; but you shall do only the thing that I tell you.”

So Balaam arose in the morning, saddled his donkey, and went with the leaders of Moab. The Angel and Balaam

But God was angry that he was going, and the angel of the Lord took his stand in the road as an adversary against him. Now he was riding on his donkey, and his two servants were with him.