NOTES for Rev 21:4
The end of time today appears to many as a kind of final catastrophe, after which, if anything remains, it will certainly be fit for no life at all. The word "apocalypse" itself has come to mean the beginning of something terrible and at the same time endless and hopeless. John, meanwhile, speaks of something else.
He speaks of a new age and of a world renewed by God's breath. Of a new heaven and a new earth. And this new world appears not somewhere in cosmic distances, on another planet or in another dimension, but here, on our earth, beside us and around us. Nature does not disappear; it changes, gains a new quality, begins to function according to other laws.
One consequence of such changed functioning is the fact that neither sickness nor death will have any place in the renewed world. This is not surprising: human nature also changes. It is renewed. And the main meaning of the changes taking place is that this renewed nature is no longer subject to evil. In spiritual life evil appears as sin; in natural life, as entropy. Neither one nor the other has a place in the renewed world. But if so, then there can be no place in it for either sickness or death. Both are precisely typical examples of the triumph of entropy, decay, degradation.
Of course, when it concerns a human being, one must speak not only of nature, but also of spirit. Man is the only creature in nature whose life is determined not by the natural component, but by the spiritual one. Even in his present state, man as a natural being strongly depends on his spiritual state. And in the new quality, after the transformation of human nature, this dependence becomes still stronger.
Now a person's physical condition is completely determined by his spiritual state. And the spiritual state of a person living in the Kingdom is by definition full. In other words, he lives a full life. The life of the Kingdom in all its fullness. And therefore the physical life of such a person on the new earth under the new heaven will also by definition be full. Without sickness and death. In all fullness.