John Gill Commentary Numbers 22:25

"And the ass saw the angel of Jehovah, and she thrust herself unto the wall, and crushed Balaam`s foot against the wall: and he smote her again." — Numbers 22:25 (ASV)

And when the ass saw the angel of the Lord
In the same position as before, with a drawn sword in his hand, and being frightened again, and in a narrow path, and no way to turn aside:

she thrust herself unto the wall ;
to one of the walls, as close as she could, in order to get by the angel:

and crushed Balaam's foot against the wall ;
running up so very closely to it:

and he smote her again ;
having done it once before, (Numbers 22:23) the times of smiting are observed, for the sake of what the ass after said, and for the confirmation of it.