What does the new heaven and new earth mean for the millennial kingdom?
The new heaven and new earth means the millennial Kingdom is interrupted and lifted off the planet long enough for a whole new planet to appear. After the thousand-year reign, this planet has used up its usefulness; the Kingdom's Eden-like aspects continue into eternity on a new earth, not floating on a cloud.
Les explains that after the great white throne sends the lost to the lake of fire, chapter 21 presents a new heaven and a new earth. He says this means the Kingdom is going to be interrupted and lifted off the planet long enough for a whole new planet to come on the scene. By the end of the thousand-year reign, this planet will have used up its usefulness. In its place comes the new heaven and new earth, and he feels the aspects that were in the Kingdom on this Garden of Eden earth will simply go right on into the new heavens and new earth, which he thinks will be a carbon copy of the Kingdom seen in Revelation and the Old Testament. That will then be eternity, and believers will spend eternity not floating on a cloud but in a Kingdom on a new earth.
And I saw a new heaven and a new earth: for the first heaven and the first earth were passed away; and there was no more sea.