The Destruction of Assyria. This is usually regarded as a genuine fragment by Isaiah, asserting, as in Isaiah 10:5-34, the approaching destruction of Assyria in Palestine, and uttered probably not long before Sennacherib's invasion in 701. Some take it to be post-exilic, mainly on the ground that, just as in the later eschatology, the judgment is to be inflicted on all the nations, while Isaiah limits his view to a much narrower horizon. It is also said to be put together out of Isaianic phrases. It is true that numerous parallels occur in the other prophecies, but the piece is so free and vigorous in style, that it does not make the impression of having been composed by a mere copyist. Nor was it possible for the Assyrian Empire to be broken up without affecting the other nations in a vital and far-reaching way. The view taken of a fragment like this necessarily depends to a large extent on the attitude adopted to some of the larger critical questions raised by the book.
Yahweh has sworn to accomplish His purpose of breaking Assyria to pieces in the mountainous land of Palestine. It is a purpose of world-wide import, and, since Yahweh has decreed it, none will be able to thwart His design.
Isaiah 14:25 a. The destruction takes place in Yahweh's land, that it may be plain to the world that Yahweh has accomplished it. It was a common feature in Apocalyptic that the judgment on the nations should take place before Jerusalem.
Isaiah 14:25 b. Perhaps a gloss. We are not told whom the prophet means by them. If the passage is original here, this should have been clearly expressed. We naturally think of the people of Judah as in the writer's mind, but the next verse contemplates a wider field. Besides, Isaiah 14:26 connects better with Isaiah 14:25 a than with Isaiah 14:25 b. It is very similar to Isaiah 10:27 (cf. Isaiah 9:4), and may have been written on the margin and then admitted to the text.