Numbers 22:21-24

So Balaam arose in the morning, and saddled his donkey and went with the leaders of Moab. But God was angry because he was going, and the angel of the LORD took his stand in the way as an adversary against him. Now he was riding on his donkey and his two servants were with him. When the donkey saw the angel of the LORD standing in the way with his drawn sword in his hand, the donkey turned off from the way and went into the field; but Balaam struck the donkey to turn her back into the way. Then the angel of the LORD stood in a narrow path of the vineyards, with a wall on this side and a wall on that side.