On this mountain…the Lord will destroy the veil that veils all peoples and remove from the whole earth the reproach of his people. The Mountain of the Lord (also called the mountain of the Lord’s house) is a concept that features prominently in the Hebrew Scripture. It is often synonymously identified with Jerusalem (both the real and apocalyptic one), and for a good reason. Jerusalem is the city of God, a place where God has chosen to dwell. Anybody who wanted to meet and converse with God had to make it to Jerusalem (temple). In the Messianic (apocalyptic) literature, Jerusalem retains this prominence. While it is not clear whether it is the present Jerusalem that will be transformed to match the needs of the time (hence the title  New Jerusalem), or whether it is the concept that will endure, one thing is clear: Jerusalem it will be. 
Of the many features of the Messianic Jerusalem that are celebrated is the fullness of life. Many nations will stream to this place because of the many good things that are found there. It will be a place for new creation. The peoples of the earth will be made into a single nation, and men and women will be able to look God in the face with no fear of dying (the ancient curse). For Christians, the understanding is that in Jesus Christ this movement towards the fullness of live has already begun. As the full revelation of God, Jesus Christ has already done away with the ancient curse and enabled us to look at the face of God. In Jesus Christ, we have already been given access to the fullness of life that is found only in God. His second coming for which we all long will thus be the culmination of what has already begun. When we therefore anticipate in celebration his second coming, we do so in the knowledge that he is coming to lead us to the source of the fullness of life.