"Go, my people, enter your rooms and shut the doors behind you; hide yourselves for a little while until his wrath has passed by. See, the Lord is coming out of his dwelling to punish the people of the earth for their sins. The earth will disclose the blood shed on it; the earth will conceal its slain no longer." NIV translation
Isaiah now speaks of the short period of time between the end of the Millennial Reign and the final judgment of all mankind. He urges them to take cover and to hold on until God has dealt with the evil of the world. We do not know how long it takes for these events to unfold but we are sure that God protects His people.
During this period of time, Satan is released again from the Abyss and is allowed to roam the earth. John tells us of this time, in Revelation 20, and we see that men are still deceived by the devil into thinking that they can overthrow the kingdom of God.
The devil will gather these people and come against the city of Jerusalem. Jesus, once again, intervenes on behalf of His people and the battle is very short.
The final judgment of all mankind follows as the dead that did not accept Jesus Christ are raised to be judged.