Numbers 22:21-25

²¹And Bil'am rose up in the morning, and saddled his ass, and went with the princes of Moab.

²²And the anger of God was kindled, because he went; and an angel of the Lord placed himself in the way to be a hindrance to him; and he was riding upon his ass, and his two servants were with him.

²³And the ass saw the angel of the Lord standing in the way, with his sword drawn in his hand; and the ass turned aside out of the way, and went into the field: and Bil'am smote the ass, to make her turn into the way.

²⁴But the angel of the Lord stepped into a path between the vineyards, with a wall on this side, and a wall on that side.

²⁵And when the ass saw the angel of the Lord, she forced herself against the wall, and pressed Bil'am's foot against the wall: and he smote her again.