The threats of this verse are all vague and general, for there is no reason to suppose that the phrase," the hills did tremble, "refers to an actual earthquake. That there was an earthquake in the reign of Uzziah is, indeed, clear from Amos 1:1; but it was probably a thing of the past when Isaiah wrote this chapter, and he is spiking of the future.
A "trembling of the hills" is, in prophetic language, a commotion among the chief men of the land. He hath stretched forth his hand. Again the "perfect of prophetic certitude." Their carcasses were torn; rather, were as refuse (comp.
Lamentations 3:45). There would be many slain, and lying unburied, in the streets of Jerusalem. For all this, etc. (comp. Isaiah 9:12, Isaiah 9:17, Isaiah 9:21, and Isaiah 10:4, where the same words are used as a refrain).
The words imply that God's judgment upon Judah will not be a single stroke, but a continuous smiting, covering some considerable space of time.