Revelation is a book of signs (1:1). New Jerusalem is the consummate sign in Revelation and in the Bible. It is God and all His redeemed people living in mutuality.
Here is an excerpt* about New Jerusalem from the ministry of Witness Lee.
The New Jerusalem is not an actual city just as the lampstands are not actual lampstands but signs of the churches [Rev. 1:20]. The New Jerusalem is a great sign of the totality of all God’s chosen, redeemed, regenerated, and transformed people. The church today is a house, the house of the living God (1 Tim. 3:15). The house of God today is not an actual house but the totality of God’s people. The church today as God’s temple, God’s house, God’s building, is not an actual physical building but is a sign signifying that the church’s function is to be a house in which the Triune God can dwell.
Today the church is a house, and in eternity the church will be enlarged. When the church is enlarged, it becomes a city. The church as a house is not an actual physical house in the same way that the church enlarged to be the holy city will not be an actual physical city. The New Jerusalem is a city signifying the church’s function in eternity to be God’s dwelling place.
The church today, all the believers in Christ Jesus built together in Him, is a precursor of New Jerusalem. Many verses in the New Testament present this view, and no verse treats the church as a physical building.
Ephesians 2:19-20 declares that we are “members of the household of God, being built…” We, not a physical structure, get built together. Verse 21 continues, “In whom [Christ Jesus] all the building, being fitted together, is growing into a holy temple in the Lord.” We are being built together in Him, not in a physical location. Also, this building is growing because its essence is the divine life.
First Peter 2:4-5 tells us that “coming to Him, a living Stone…you yourselves also, as living stones, are being built up as a spiritual house.” Very clear. This is the living house of the living God in 1 Timothy 3:15.
Other verses in the New Testament say the same: we are the materials being built together, the building process is growth in the divine life, and the building work is going on in Christ. These same characteristics are true of New Jerusalem, which is the consummation of all the building and growth in the Bible.
* Witness Lee, The Divine Economy, Chapter 15, published and © by Living Stream Ministry. Read more of this excerpt online. Many other books by Witness Lee may be read online here.