And he will cut down the thick places of the forest with iron. There is no difficulty in explaining this metaphor, for it is plain enough that by tall and high trees is denoted all that is powerful, excellent, or lofty. Thus he foretells the destruction and ruin of Judea, which he compares to the cutting down of a forest; by which he means that there is nothing so valuable that the enemies will not destroy it, till they have stripped the whole land of its ornaments. And Lebanon will fall violently. He mentions Lebanon, because that mountain, as we all know, was highly celebrated for fruitful and highly valuable trees. Now, if he had been speaking of the Assyrians, it would not have been appropriate to introduce the destruction of Lebanon. Hence we infer that the Prophet, in this passage, again threatens the Jews; and this agrees well with the introduction of the discourse, for it begins with a word which calls attention, Behold.

And he shall cut down the thickets of the forest - The army of the Assyrians, described here as a thick, dense forest; compare Isaiah 10:18-19.
With iron - As a forest is cut down with an axe, so the prophet uses this phrase here, to keep up and carry out the figure. The army was destroyed with the pestilence 2-Kings 19:35; but it fell as certainly as a forest falls before the axe.
And Lebanon - Lebanon is here evidently descriptive of the army of the Assyrian, retaining the idea of a beautiful and magnificent forest. Thus, in Ezekiel 31:3, it is said, 'the king of the Assyrians was a cedar of Lebanon with fair branches.' Lebanon is usually applied to the Jews as descriptive of them (Jeremiah 22:6, Jeremiah 22:23; Zac 10:10; 11: l), but it is evidently applied here to the Assyrian army; and the sense is, that that army should be soon and certainly destroyed, and that, therefore, the inhabitants of Jerusalem had no cause of alarm; see the notes at Isaiah. 37.

Lebanon shall fall by a mighty one - באדיר beaddir, the angel of the Lord, who smote them, Kimchi. And so Vitringa understands it. Others translate, "The high cedars of Lebanon shall fall:" but the king of Assyria is the person who shall be overthrown.

And he shall cut down the thickets of the forest with iron,.... The multitude of the common soldiers, the whole body of the army, by means of one of his angels, that excel in strength, for which he is compared to "iron"; and which is explained in the next clause:
and Lebanon shall fall by a mighty one; the Assyrian army is compared to the forest of Lebanon, for the multitude of trees in it, and the tallness of its cedars, it abounding not only with common soldiers, but with great men; so it is compared to a forest, and to Carmel, or a fruitful field, in Isaiah 10:18 and the Assyrian monarch is said to be a cedar in Lebanon, Ezekiel 31:3 which fell by the hands of one of the mighty angels, 2-Kings 19:35 some, because of this last clause, think that this and the preceding verse Isaiah 10:33 are to be understood of the calamities that should come upon the Jews, at the time of the Babylonish captivity; for though Sennacherib should stop at Nob; and proceed no further, however should not be able to take Jerusalem, yet hereafter a successor of his should; and, according to this sense, by the "bough" lopped may be meant Jeconiah, or Zedekiah king of Judah; by the "high ones of stature", and the "haughty" ones, his children, the princes of the blood, and the nobles of the land; and by the "thickets of the forest", the common people, who were either killed or carried captive; and by Lebanon, the temple, Zac 11:1 and by the "mighty one", Nebuchadnezzar that burnt it. And some of the ancient Jews interpret this last clause of the destruction of the temple by Vespasian; they observe upon this passage in one place (m), there is no mighty one but a king, as in Jeremiah 30:21 and there is no Lebanon but the house of the sanctuary, according to Deuteronomy 3:25 wherefore when a certain Jew saluted Vespasian as a king, and he replied that he was no king, the Jew made answer, if thou art not a king, thou shall be one; for this house (meaning the temple) shall not be destroyed but by the hands of a king, as it is said, "and Lebanon shall fall by a mighty one" (n).
(m) T. Bab. Gittin, fol. 56. 2. (n) Midrash Echa Rabbati, fol 46. 4.

This verse and Isaiah 10:33 describe the sudden arrest and overthrow of Sennacherib in the height of his success; Isaiah 10:18-19; Ezekiel 31:3, Ezekiel 31:14, &c., contain the same image; "Lebanon" and its forest are the Assyrian army; the "iron" axe that fells the forest refers to the stroke which destroyed the one hundred and eighty-five thousand Assyrians (2-Kings 19:35). The "Mighty One" is Jehovah (Isaiah 10:21; Isaiah 9:6).
From the local and temporary national deliverance the prophet passes by the law of suggestion in an easy transition to the end of all prophecy--the everlasting deliverance under Messiah's reign, not merely His first coming, but chiefly His second coming. The language and illustrations are still drawn from the temporary national subject, with which he began, but the glories described pertain to Messiah's reign. Hezekiah cannot, as some think, be the subject; for he was already come, whereas the "stem of Jesse" was yet future ("shall come") (compare Micah 4:11, &c.; Micah 5:1-2; Jeremiah 23:5-6; Jeremiah 33:15-16; Romans 15:12).

Iron - Or, as with iron, as the trees of the forest are cut down with instruments of iron. Lebanon - Or, his Lebanon, the Assyrian army, which being before compared to a forest, and being called his Carmel in the Hebrew text, Isaiah 10:18, may very fitly upon the same ground, be called his Lebanon here.