What is meant by the New Jerusalem?
The very word Jerusalem means City of Peace. The New Jerusalem means the finally established and spiritual Kingdom of Christ, in which He will reign in eternal happiness and peace with those who are saved. Let us suppose that the world has ended, and that there are some souls in heaven and some souls in hell. Some will be in heaven, and some will be in hell. On the one hand some will be enjoying unlimited happiness; on the other, suffering unlimited misery. Neither the happiness nor the misery will be unlimited.