The book of Micah describes God's coming judgment on Israel because of its rebellion. The Assyrian Empire and then the Babylon Empire would destroy the nation and leave Jerusalem in ruin. However, Micah also gives the people hope. Like a shepherd, God will one day gather and restore a faithful remnant to the land. He will rebuild Jerusalem, defeat evil forever, set a Messianic King to rule over the people and bless all the nations.
Before that can happen, though, He must confront and judge evil from among His people. Then He can show mercy and fulfill His covenant promise to Abraham and bless all the nations through Israel. His ultimate purpose is not to destroy Israel but to redeem and save the world.