Jerusalem = "set ye double peace"
 1) denotes either the city itself or the inhabitants
 2) "the Jerusalem that now is", with its present religious
    institutions, i.e. the Mosaic system, so designated from its
    primary external location
 3) "Jerusalem that is above", that is existing in heaven,
    according to the pattern of which the earthly Jerusalem was
    supposed to be built
    3a) metaph. "the City of God founded by Christ", now wearing the
        form of the church, but after Christ's return to put on the
        form of the perfected Messianic kingdom
 4) "the heavenly Jerusalem", that is the heavenly abode of God,
    Christ, the angels, saints of the Old and New Testament
    periods and those Christians that are alive at Christ's return
 5) "the New Jerusalem", a splendid visible city to be let down
    from heaven after the renovation of the world, the future
    abode of the blessed