Chapters 2-4 of Isaiah make up the second of the seven part chiasm in the first section of the book. And that section is itself chiastic in structure. The beginning (2:2-5) declares the future exaltation of Jerusalem, and the end (4:2-6) the future restoration of Jerusalem (Dorsey).
4:2 "In that day the Branch of Yahweh shall be beautiful and glorious..." - The Branch is going to be used in 11:1 and 53:2 to identify the Messiah, clearly appealed to in the New Testament as the coming forth of Jesus. However, here, it is Israel herself who is being described. This is not a problem, for Jesus is the New Israel, the Branch coming forth from the stump of unbelief and rebellion.
What does this Branch bring forth? "...And the fruit of the earth shall be excellent and appealing for those of Israel who have escaped" 4:2b.
Judgement is at the center (chapter 3). But there is fruit from this cleansing, and as Isaiah pictures all over, this fruit goes all over the earth. This judgment is also a chastisement from Yahweh, and as Hebrews says, "brings the peaceable fruit of righteousness."
Whenever judgment befalls a people, the righteous must look up and ahead. God is up to something. Something wonderful.