Since divine truth is the light in the heavens, all true things are luminous there wherever they occur—whether within an angel, outside of an angel, within the heavens, or outside of the heavens. Still, the truths outside the heavens do not shine the way the truths inside the heavens do. The truths outside the heavens shine coldly, like something snowy, without warmth, because unlike truths within the heavens, they do not derive their essence from what is good. So that cold light disappears at the touch of heaven’s light; and if there is some underlying evil, it turns to darkness. I have seen this several times, along with many other remarkable things concerning luminous truths, which I forego for now.
Something now needs to be said about heaven’s warmth. In its essence, heaven’s warmth is love. It emanates from the Lord as the sun, which is divine love for the Lord and from the Lord, as has been explained in the preceding chapter. We can therefore see that heaven’s warmth is just as spiritual as its light, because they come from the same source.
There are two things that emanate from the Lord as the sun, divine truth and divine good. Divine truth comes out in heaven as light and divine good as warmth. However, divine truth and divine good are so united that they are not two, but one. For angels, though, they are separated. There are angels who accept divine good more readily than divine truth, and there are angels who accept divine truth more readily than divine good. The ones who are more open to divine good are in the Lord’s heavenly kingdom; the ones who are more open to divine truth are in the Lord’s spiritual kingdom. The most perfect angels are the ones who are equally open to both.
from Heaven and Hell, Sections 132, 133