John Gill Commentary Numbers 22:24

"Then the angel of Jehovah stood in a narrow path between the vineyards, a wall being on this side, and a wall on that side." — Numbers 22:24 (ASV)

But the angel of the Lord stood in a path of the vineyard ,
&c.]. Which were in the field into which the ass went, and before Balaam could turn her back she got into a narrow path, between the vineyards, as the Targum of Jonathan; a footpath which lay between them, or a footpath where foxes ran and had their holes, who used to lie near vineyards and among them, see (Song of Solomon 1:14) however, it was a very narrow path, and here the angel placed himself, so that there was no passage for Balaam and his ass, at least not without great difficulty and danger;

a wall [being] on this side, and a wall on that side ;
and therefore there was no going out into the field, as before, to avoid the difficulty and danger; this being, as Jarchi observes, a stone wall that was on each side.