new heavens, &c.: i.e. new, in respect to the old. Not the "new" of 2 Peter 3:13, or Revelation 21:1. Note the contrast of this with the only two references to the history of Revelation 21 :
Name, Jerusalem (Hephzi'bah, Isaiah 65:18)
Position, on mountain (Isaiah 65:25).
Privileges, Isaiah 65:18-20.
Character, sinners there (Isaiah 65:20).
Character, prayer (Isaiah 65:24).
Employment, labour, planting, building (Isaiah 65:21).
New Jerusalem (Revelation 21:2) ;
"great", "holy" (Revelation 21:10).
out of heaven (Revelation 21:2).
no sinners (Revelation 21:27).
no temple (Revelation 21:22).
already built by God (Revelation 21:12-25; Revelation 22:3-5).