Num 22:26-27
The angel moved still farther, and stationed himself in front of him, in so narrow a pass, that there was no room to move either to the right or to the left. As the ass could neither turn aside nor go past this time, she threw herself. down. Balaam was still more enraged at this, and smote her with the stick (בּמקּל, which he carried; see Gen 38:18).