They; the flies, and especially the bees. Shall rest all of them; they shall have an easy victory; few or none of them shall be slain in the attempt. The desolate valleys; either,
1. Such as were and had long been desolate. So it signifies the vast numbers of their enemies, which filled all places, both such as were well inhabited, and such as were in a great measure desolate. Or,
2. Such as they found very fruitful, but made them desolate. The rocks; to which possibly the Israelites fled for refuge. Bushes; which he mentions, partly because flies and bees use frequently to rest there, and partly to intimate that no place should escape the fury of this enemy.