The next thing is to try to imagine is the spectacular beauty of the New Jerusalem.
It starts with the wall. As mentioned, the wall is not defensive. It is more like the walls of a spaceship. It is for moving. But once this thing arrives on the New Earth, you can also see it is for the sake of beauty. Most walls are eyesores, but not this one. Though thick, about 200 feet thick, it is transparent like a crystal. In the case of this city, it is a giant cube with the city clearly visible inside.
The city must have a direction orientation (this side up) because John speaks of the foundation. The foundation has a beauty of its own with layers that can be described in terms of crystals found on Earth now. The walls have gates, but only 12. These are described as being like giant pearls. I doubt they are the product of massive oysters, but the look is similar.
Another point of contact with the current planet is found in Revelation 21:24:
And the kings of the Earth will bring their splendor into it.
What is beautiful and worthy from this present Earth will find its way into the eternal city. What will make the cut, only God knows.
The important part is that we “make the cut”. Our salvation does not rest on being more beautiful or better than others. It rests on the forgiveness that comes through Jesus Christ. We can only be there as cleansed and renewed people.
Nothing impure will ever enter it, nor will anyone who does what is shameful or deceitful, but only those whose names are written in the Lamb’s book of life.