21:2 I saw the holy city, New Jerusalem, coming down out of heaven from God,
made ready like a bride adorned for her husband.
21:3 I heard a loud voice out of heaven saying,
 

"Behold, God's dwelling is with people, and he will dwell with them,
and they will be his people, and God himself will be with them as their God.
21:4 He will wipe away from them every tear from their eyes.
Death will be no more; neither will there be mourning,
nor crying, nor pain, any more.
The first things have passed away."

21:5 He who sits on the throne said,
 

"Behold, I am making all things new."He said,
"Write, for these words of God are faithful and true."

21:6 He said to me,
 

"It is done! I am the Alpha and the Omega, the Beginning and the End.
I will give freely to him who is thirsty from the spring of the water of life.
21:7 He who overcomes, I will give him these things.
I will be his God, and he will be my son.
21:8 But for the cowardly, unbelieving, sinners, abominable, murderers, sexually immoral, sorcerers, {The word for "sorcerers" here also includes users of potions and drugs.} idolaters, and all liars, their part is in the lake that burns with fire and sulfur, which is the second death."

21:9 One of the seven angels who had the seven bowls,
who were loaded with the seven last plagues came, and he spoke with me, saying,
"Come here. I will show you the wife, the Lamb's bride."
21:10 He carried me away in the Spirit to a great and high mountain,
and showed me the holy city, Jerusalem, coming down out of heaven from God,
21:11 having the glory of God.

Her light was like a most precious stone, as if it was a jasper stone, clear as crystal;
21:12 having a great and high wall; having twelve gates, and at the gates twelve angels;
and names written on them, which are the names of the twelve tribes of the children of Israel.
21:13 On the east were three gates; and on the north three gates;
and on the south three gates; and on the west three gates.

21:14 The wall of the city had twelve foundations,
and on them twelve names of the twelve Apostles of the Lamb.
21:15 He who spoke with me had for a measure, a golden reed,
to measure the city, its gates, and its walls.
21:16 The city lies foursquare, and its length is as great as its breadth.
He measured the city with the reed, Twelve thousand twelve stadia
{12,012 stadia = or 2,221 kilometers or 1,380 miles. TR reads 12,000 stadia instead of 12,012 stadia.}. Its length, breadth, and height are equal.

21:17 Its wall is one hundred forty-four cubits,
{144 cubits is about 65.8 meters or 216 feet} by the measure of a man, that is, of an angel.
21:18 The construction of its wall was jasper. The city was pure gold, like pure glass.
21:19 The foundations of the city's wall were adorned with all kinds of precious stones.
The first foundation was jasper; the second, sapphire{or, lapis lazuli};
the third, chalcedony; the fourth, emerald;
21:20 the fifth, sardonyx; the sixth, sardius; the seventh, chrysolite;
the eighth, beryl; the ninth, topaz; the tenth, chrysoprasus;
the eleventh, jacinth; and the twelfth, amethyst.

21:21 The twelve gates were twelve pearls. Each one of the gates was made of one pearl.
The street of the city was pure gold, like transparent glass.

21:22 I saw no temple in it, for the Lord God, the Almighty, and the Lamb, are its temple.
21:23 The city has no need for the sun, neither of the moon, to shine,
for the very glory of God illuminated it, and its lamp is the Lamb.
21:24 The nations will walk in its light.
The kings of the earth bring the glory and honor of the nations into it.
21:25 Its gates will in no way be shut by day (for there will be no night there),
21:26 and they shall bring the glory and the honor of the nations into it so that they may enter.
21:27 There will in no way enter into it anything profane,
or one who causes an abomination or a lie,
but only those who are written in the Lamb's book of life.

vs 2 The New Jerusalem is the corporate body of Christ. It is composed of all the redeemed for all generations. Notice its contrast with Babylon.
 

This metaphor of identifying a city with a category of people was also used by Paul in the book of Galatians.

"For this Agar is mount Sinai in Arabia, and answereth to Jerusalem which now is, and is in bondage with her children. But Jerusalem which is above is free, which is the mother of us all."Gal 4:25,26

vs 3 It's amazing the thought of God dwelling with men. Even Solomon after he built the temple declared: "But will God in very deed dwell with men on the earth? behold, heaven and the heaven of heavens cannot contain thee; how much less this house which I have built!" 2Ch 6:18 Nonetheless, it will be as if God were dwelling with men among his redeemed. The temple represented the presence of God on earth. But God himself will have his presence among the redeemed.

vs 4 I would infer that the promise of no death or mourning or crying or pain applies specifically to the redeemed. For they certainly don't apply to those thrown in the lake of fire. But wouldn't it be rather heartless to not grieve over the suffering of those in hell? I suspect not due to a change of perspective. I suspect any such grieve will be replaced with a sense that justice is being satisfied, as for example in the case of rejoicing over the destruction of Babylon.

vs 5 "I am making everything new!" These words summarize the good news. Sin and its affects are going to be done away with. The believers are spiritually redeemed and physically redeemed, having both reborn of the Spirit of God and transformed by that same Spirit.

vs 6 What me do now to be assured a place in the New Jerusalem? If we thirst for this destiny, we must drink of the water of life, which is free. Jesus spoke of this to the woman at the well in John 4.

"Jesus answered and said unto her, If thou knewest the gift of God, and who it is that saith to thee, Give me to drink; thou wouldest have asked of him, and he would have given thee living water." John 4:10

"And the Spirit and the bride say, Come. And let him that heareth say, Come. And let him that is athirst come. And whosoever will, let him take the water of life freely." Rev 22:17

"For this is the love of God, that we keep his commandments: and his commandments are not grievous. For whatsoever is born of God overcometh the world: and this is the victory that overcometh the world, even our faith." 1John 5:3,4

vs 8 Notice the similarity between this list and that given in

"Know ye not that the unrighteous shall not inherit the kingdom of God? Be not deceived: neither fornicators, nor idolaters, nor adulterers, nor effeminate, nor abusers of themselves with mankind, Nor thieves, nor covetous, nor drunkards, nor revilers, nor extortioners, shall inherit the kingdom of God." 1Cor 6:9,10

Cowardice in particular seems out of place, yet is mentioned first on the list. It is written in proverbs that "The wicked flee when no man pursueth: but the righteous are bold as a lion." Pr 28:1 If your life is characterized by cowardice, or any of these other characteristics, then you have not been born of God. See also Free Grace Theology vs The Bible

vs 9-21 In the description of the New Jerusalem, one must keep in mind that it is just speaking metaphorically. The New Jerusalem is not actually a building, but composed of individuals who corporately make up the body of Christ. Historical post-Biblical Christian has made to much of "buildings" and "institutions" much to the detriment of the body of Christ.

From the description, one gets a sense of unity, symmetry, value, strength and stability.

vs 21 I heard a story of a rich man who wanted to take it with him. So he was buried with a suitcase of gold bars. When he came to the gates of heaven, he asked Peter if he could take the suitcase in. Peter looked at the gold bars baffled but let him in. And the man entered joyfully. Another man asked Peter what was in the suitcase. Peter answered "pavement!". (Just kidding!)

vs 22 As in Jerusalem, the temple represents the presence of God. But just as the curtain of the temple was torn in half when Christ died symbolizing our reconciliation with God, so the temple itself is taken away entirely representing the actualization of our intimacy with God.

vs 24-27 The kings who enter it are among the redeemed, for nothing impure can enter it. The kings are we who are redeemed and who will rule with Christ. It is not speaking of the kings of this age. Only those who names are written in the book of life shall enter it. And logically since no one who does what is shameful or deceitful shall enter, this implies that the redeemed no longer sin, but have perfect Christlike behavior.