John Wesley on Revelation 21:2

And I saw the holy city - The new heaven, the new earth, and the new Jerusalem, are closely connected. This city is wholly new, belonging not to this world, not to the millennium, but to eternity. This appears from the series of the vision, the magnificence of the description, and the opposition of this city to the second death, Rev 20:11,12; 21:1,2,5,8,9; 22:5. Coming down - In the very act of descending.