Revelation 21

     And so the end is actually a new beginning. Old corrupt earth is replaced with a new heaven and a new earth. Notice that "the sea is no more". The ancient Hebrews were not sea faring people. The sea in Hebrew literature generally referred to untamed and unrestrained chaos. With the new heaven and new earth there is no place for chaos and so the sea is no more.
    The Bible begins in Genesis with the creation of a garden and the image of Adam and Eve "walking with God in the coolness of the evening breeze." Here in Revelation, when it is all said and done, we are back to a garden and the dwelling of God is with humans. Notice, in the end people don't go to heaven -- heaven comes to us. God wipes tears and eliminates death and mourning and crying and pain in this new city.
     The vision of the new Jerusalem is drawn heavily from the prophet Ezekiel. Notice the "pearly gates (21:21) and the "streets paved with gold". Notice that the gates are the 12 tribes but the foundations are the 12 apostles. Notice the enormous size of the city (1500 x 1500 miles {12,000 stadia}). For a geographically small country like Israel (that is 120 miles by 40 miles) the size of this one city is unthinkably huge. The shape of the city is the shape of the "holy of holies" in the ancient temple in Jerusalem -- it is a perfect cube.
     The key for John's readers is all of the imagery that would be read as unimaginable sense of security. The walls (symbol of protection) are nearly a football field high but more important is the promise that "the gates will never be shut by day and there will be no night there." The language describes a city that has no remaining enemies and a populace that will never know fear. It is a city that has no need of a place of worship (there is no temple 21:22) because God is present and the Lamb of God (Jesus) is always present there.
    One other peculiar thing. Mark Twain once commented that God created light before God created the sun, moon and the stars. Twain thought this was unlikely and impossible. What Twain failed to understand is that the light created is the very Glory of God -- so too here in Revelation 21 there is no need for sun or moon -- the glory of God is the light of the city. Notice also that Lamb is the lamp. Remember the lamp stands and the Angels in the first part of Revelation? There is no "guardian angel" for this new Jerusalem. Jesus himself, the Lamb of God, is the lamp for this city.