Heaven is called God’s dwelling and God’s throne, so people think that God lives there like a monarch in a realm. However, God—that is, the Lord—is in the sun above the heavens and is in the heavens by means of his presence in warmth and light, as I have explained in the last two sections. Further, even though the Lord is present in heaven in this apparently distant way, he is still also intrinsically present there, so to speak, since as I have just explained in Sections 103–112 the distance between the sun and heaven is not a distance but a virtual distance. Given the fact that this distance is only apparent, then, it follows that the Lord himself is in heaven. He is in the love and wisdom of heaven’s angels; and since he is in the love and wisdom of all the angels and the angels make up heaven, he is in all of heaven.
The reason the Lord is not only in heaven but actually is heaven itself is that love and wisdom make an angel, and these two are properties of the Lord in the angels. It therefore follows that the Lord is heaven.
Angels are not angels because of anything that belongs to them. What belongs to them is just like what belongs to us—evil. The reason this is what belongs to angels is that all angels were once earthly people, and this attribute clings to them from their birth. It is simply moved aside, and to the extent that it is, they accept love and wisdom, or the Lord, into themselves.
With a little elevation of understanding, everyone can see that it is quite impossible for the Lord to dwell with angels in anything but what is his, that is, what belongs to him, which is love and wisdom. He cannot dwell in anything that belongs to the angels, which is evil. This is why the Lord is in them, and they are angels, to the extent that evil is moved aside. The actual angelic essence of heaven is divine love and wisdom. This divine reality is called “angelic” when it is in angels; so again we can see that angels are angels because of the Lord and not on their own. The same therefore holds true for heaven as well.
Still, there is no understanding how the Lord is in an angel and an angel is in the Lord except through knowing what kind of union is involved. It is a union of the Lord with the angel and of the angel with the Lord, so it is a reciprocal union. On the angel’s side, it is like this. Angels, like us, simply feel as though they participate in love and wisdom on their own, and therefore that love and wisdom are theirs, their very own. If they did not feel this way there would be no union, so the Lord would not be in them, nor they in the Lord. It cannot happen that the Lord is in any angels or people unless they, as subjects of his presence in love and wisdom, sense and feel this as their own. This enables them not only to accept but also to retain what they have accepted, and to love in response. This, then, is how angels become wise and remain wise. Can people decide to love God and their neighbor, can people decide to gain wisdom, unless they feel and sense that what they love, learn, and gain is their own? Can they retain anything in themselves otherwise? If it were not for this, then the inflowing love and wisdom would have no seat. They would flow right through without making any difference; and as a result angels would not be angels and people would not be human. They would be virtually lifeless.
It makes sense, then, that if there is to be union, there must be reciprocity.
from Divine Love and Wisdom, Sections 113-115