9-10 Then one of the seven angels who held the seven bowls containing the seven last plagues came and said to me, “Come with me! I will show you the bride, the wife of the Lamb.” So he took me in the Spirit to a great, high mountain, and he showed me the holy city, Jerusalem, descending out of heaven from God. 11-12 It shone with the glory of God and sparkled like a precious stone - like jasper as clear as crystal. The city wall was broad and high, with twelve gates guarded by twelve angels. And the names of the twelve tribes of Israel were written on the gates. 13-14 There were three gates on each side - east, north, south, and west. The wall of the city had twelve foundation stones, and on them were written the names of the twelve apostles of the Lamb.

15-16 The angel who talked to me held in his hand a gold measuring stick to measure the city, its gates, and its wall. When he measured it, he found it was a square, as wide as it was long. In fact, its length and width and height were each 1,400 miles. 17-20 Then he measured the walls and found them to be 216 feet thick  (according to the human standard used by the angel). The wall was made of jasper, and the city was pure gold, as clear as glass. The wall of the city was built on foundation stones inlaid with twelve precious stones: the first was jasper, the second sapphire, the third agate, the fourth emerald, the fifth onyx, the sixth carnelian, the seventh chrysolite, the eighth beryl, the ninth topaz, the tenth chrysoprase, the eleventh jacinth, the twelfth amethyst. 21 The twelve gates were made of pearls - each gate from a single pearl! And the main street was pure gold, as clear as glass.

22-23 I saw no temple in the city, for the Lord God Almighty and the Lamb are its temple.  And the city has no need of sun or moon, for the glory of God illuminates the city, and the Lamb is its light. 24-26 The nations will walk in its light, and the kings of the world will enter the city in all their glory. Its gates will never be closed at the end of day because there is no night there. And all the nations will bring their glory and honour into the city.  27 Nothing evil will be allowed to enter, nor anyone who practices shameful idolatry and dishonesty - but only those whose names are written in the Lamb’s Book of Life. Revelation 21:9-27 New Living Translation paraphrase (English Standard Version link)

In the vision Jesus gave to him, John saw a city descending from heaven which he was told is 'the bride of the Lamb.' It’s like when the apostle Paul said: “A man leaves his father and mother and is joined to his wife, and the two are united into one. This is a great mystery, but it is an illustration of the way Christ and the church are one.” (Ephesians 5:31-32)

Verses 11-21 describe a city of great beauty, perfection and security. The names of Israel's 12 tribes on it's gates showed the gospel's Old Testament roots, and the wall's 12 foundation stones with the apostle’s names spoke of the New Testament. The gates were open to the four points of the compass so that all the nations might come in. Paul spoke of that too when he wrote “You Gentiles are no longer strangers and foreigners - you are citizens along with all of God’s holy people. You are members of God’s family.  Together, we are his house, built on the foundation of the apostles and the prophets. And the cornerstone is Christ Jesus himself.” (Ephesians 2:19-20) But what is the important difference between this heavenly city and the Jerusalem on earth? (vs 22-23)

There was no need of a temple because Christ made the perfect once for all sacrifice. So I suggest that this vision represents the culmination of what Jesus Christ did in the world through the cross and sending out the gospel. People of all nations have become his bride. The enormous size of the city and it's precious stones show that multitudes have been saved and will be glorified. It's not so much a picture of heaven as a picture of God's people, those whose names are in the Lamb's book of life. Christians may look feeble and like nothing in this world - but their destiny is awesome! Verse 27 reminds us of who won't be part of this city - but for all who turn from such things and call on Christ for salvation, it’s gates are always open!