To verse 6, this chapter declares the manner of its accomplishment—that He found none of the people ready to assist Him, and He trod the wine press of vengeance alone, on the infidel peoples; it would seem that it was of them, not including the Jews. There was ein-ish (no man) with Him, am-mim (of the peoples). So the LXX, kai ton ethnon ouk estin aner met'emou (and of the nations there is not a man with Me), and I think, the reason for their not being called go-im (nations) is evident. From verse 7, this naturally calls out the expression of the continuity of the Lord's love and kindness towards Israel, recapitulating the necessitude of the Lord's love, and calling for exercise of it upon the ground of its former manifestation, drawing out in chapter 64 the earnest intercession of the Remnant in Spirit, i.e., the Jews, with the Lord of its salvation.
To the end of this verse we have the day of vengeance, in which Messiah, the Lord Jesus, executes vengeance in Bozrah against the peoples, according to chapter 61:2—alone, amidst the peoples, in this work.
This commences another subject—the holy and humble expression of the Spirit of grace and truth in humiliation, acknowledging grace and owning their state and evil, and counting on the favor of God towards His people, while owning all their desert in evil. This goes on down, to chapter 64: 12.