Numbers 22:21-24

And Balaam rose up in the morning, and saddled his ass, and went with the princes of Moab. And God's anger was kindled because he went: and the angel of the LORD stood in the way for an adversary against him. Now he was riding upon his ass, and his two servants were with him. And the ass saw the angel of the LORD standing in the way, and his sword drawn in his hand: and the ass turned aside out of the way, and went into the field: and Balaam smote the ass, to turn her into the way. But the angel of the LORD stood in a path of the vineyards, a wall being on this side, and a wall on that side.