Synopsis of the Books of the Bible, by John Nelson Darby, [1857-62], at sacred-texts.com
The following commentary covers Chapters 9:8-21, 10, 11, and 12.
In Isa 9:8 the Spirit, having given the great leading facts as to Messiah, Immanuel, resumes the general history of Israel without any special introduction of the Messiah till towards the end. This prophecy closes with chapter 12. Although the pride of Ephraim is mentioned, yet Jacob or Israel is looked at as a whole. The different phases of chastisement or of distress are in Verses 8-12 (Isa 9:8-12), 13-17 (Isa 9:13-17), 18-21 (Isa 9:18-21), and Isa 10:1-4. The Assyrian then re-appears, as being properly the rod of Jehovah; and it is announced, that when God shall have accomplished all that He had determined with respect to Zion (an accomplishment not here revealed), He will break the rod that He has used, and then the remnant shall seek Jehovah, and shall "stay upon" Him. This is the final act of the great drama of God's dealings with respect to Israel. There is a consumption decreed of God for the land. But when at length the Assyrian lifts up his hand, Jehovah comes in and smites him. And the indignation of Jehovah, and His anger against Israel, which till now had never been turned away, will come to an end in the destruction of this rod that magnified itself against the Lord who used it. Verse 25 (Isa 10:25) is in contrast with Isa 9:12; Isa 9:17; Isa 9:21, and Isa 10:4. Sennacherib was a type of this. But it is a prophecy of the destruction of the Assyrian in the last days, when the indignation against Israel shall cease.
Consequently we have, in chapters 11, 12, the Messiah and His reign, the source of the millennial blessing of the people of God. The first Verses of chapter 11 (Isa 11:1-5) give His character; afterwards it is the effect of His reign.