However, we do need to realize that if people are engrossed in love for themselves and love for the world, the pleasure they are feeling when they move toward some heavenly community is the pleasure of their own cravings. So it is diametrically opposed to the pleasure of heaven. They attain the pleasure of their cravings when they succeed in stealing and taking away heavenly pleasure from people who are absorbed in it. It is different when no theft or removal occurs. Then they cannot get nearer because to the extent that they do, they are plunged into pain and torment. This is why they rarely dare to approach. This too I have been shown by an abundance of experience, some of which I should like to present.
There is nothing spirits want more when they are arriving in the other life from this world than to get into heaven. Almost all of them expect to because they believe that heaven is simply a matter of being let in and accepted. Because this is what they want, then, they are taken to some community of the outmost heaven. If they are devoted to love for themselves and the world, then the moment they reach the first border of that heaven they begin to feel pain and to be so tormented within that they feel as though they were in hell rather than in heaven. So they themselves dive down headlong and are not at rest until they are with their own kind in the hells.
It has also often happened that spirits like this have wanted to find out what heavenly joy is, and when they have heard that it is within the deeper nature of angels, they have sought to share in it for themselves. So this too was done, because when spirits are not yet in heaven or in hell, whatever they want is granted if it may do any good. Once communication was established, they began to feel such agony that they did not know how to control their bodies because of the pain. It looked as though they pushed their heads down to their feet and threw themselves on the ground and twisted themselves into loops like snakes, all because of their inner agony. This was the effect that heavenly pleasure had on people whose pleasures stemmed from love for themselves and love for the world. The reason is that these loves are diametrically opposed, and when a love meets its opposite this kind of pain results. Further, since heavenly pleasure comes in by an inner path and flows into an opposing pleasure, it twists the deeper levels that are engrossed in that pleasure backward, in the opposite direction. This results in this kind of agony.
As I have already noted, the reason these loves are contrary to each other is that love for the Lord and love for our neighbor want to share everything with others. This is in fact their delight. But self-love and love for the world want to take things away from others for themselves, and find pleasure to the extent that they can succeed.
This also enables us to realize why hell is separated from heaven. It is because all the people who are in hell, while they lived in the world, were wholly focused on pleasures of the body and the flesh because of their love for themselves and love for the world; while all the people who are in heaven, while they lived in the world, were focused on pleasures of the soul and the spirit because of their love for the Lord and their love for their neighbor. Since these loves are opposed to each other, the hells and the heavens are completely separated, even to the point that spirits who are in hell do not dare stick out a single finger or raise the top of their heads, for the moment they do so, even the slightest bit, they are in torment and agony. This too I have often seen.
from Heaven and Hell, Section 400