And God made the expanse, and he made a distinction between the waters that were under the expanse and the waters that were over the expanse, and so it was done; and God called the expanse heaven. — Genesis 1:7-8
The second thing we begin to notice while being reborn, then, is that the inner self exists. We become aware that the attributes of the inner self are good feelings and true ideas, which are the Lord’s alone.
While we are being reborn, our outer self is such that it still believes we are acting on our own when we do what is good and speaking on our own when we speak what is true. The Lord uses those things—allowing them to seem like our own, since such is our mind-set—to lead us to doing what is good and speaking what is true. Consequently we first learn to distinguish what is under the expanse; only then do we learn to distinguish what is over the expanse.
Another secret from heaven is that the Lord leads us by means of things that really are our own—both the illusions of our senses and our cravings—but diverts us toward things that are true and good. So every single moment of regeneration carries us forward from evening to morning, just as it takes us from the outer self to the inner, or from earth to heaven. This is why the expanse (the inner self) is now called heaven.
Spreading out the earth and stretching out the heavens is a customary formula used by the prophets when they speak of our regeneration. In Isaiah, for example:
This is what Jehovah has said, your Redeemer and the one who formed you from the womb: “I am Jehovah, making all things, stretching the heavens out on my own and spreading the earth out by myself.” (Isaiah 44:24)
Again, where the Lord’s Coming is spoken of openly:
A crushed reed he does not break, and smoldering flax he does not quench; he propels judgment toward truth. [In other words, he does not break our illusions or extinguish our cravings but bends them toward truth and goodness. It continues:] God Jehovah creates the heavens and stretches them out. He spreads out the earth and the things it produces. He gives a soul to the people on it and spirit to everyone walking on it. (Isaiah 42:3, 4, 5)
Several other places could be cited as well.
from Secrets of Heaven, Volume 1, Section 24-25