Once again I have to confess my ignorance when it comes to understanding the Prophets. I looked some information up in the New Bible Commentary, and I think it will be more helpful than a personal commentary from me.
In the first series, Israel is sent into exile and their holy land dislocated on account of their sin (1:2–2:11). The Lord, however, promises to gather his elect remnant into Jerusalem to survive the Assyrian siege and to become their king (2:12–13). In the second series, after dismantling Jerusalem for its failed leadership (3:1–12), the Lord will exalt Jerusalem high above the nations (4:1–5) and there reassemble the afflicted remnant, who will restore God’s dominion over the earth (4:6–8). That prophecy finds fulfilment today in Jesus Christ who rules human hearts from heavenly Mt Zion (Acts 2:32–36; Heb. 12:22).