BY “the changes of angels’ states,” we mean their changes in regard to love and faith and therefore in regard to wisdom and intelligence—to the state of their life, that is. States are attributes of life and of matters that pertain to life; and since angelic life is a life of love and faith and thereby of wisdom and intelligence, states are attributes of these, and we talk about states of love and faith and states of wisdom and intelligence. Now we need to describe how these states change for angels.
Angels are not constantly in the same state as to love, and consequently they are not in the same state as to wisdom, for all the wisdom they have is from their love and in proportion to it. Sometimes they are in a state of intense love, sometimes in a state of love that is not intense. It decreases gradually from its most to its least intense. When they are in the highest level of love, they are in the light and warmth of their lives, or in their greatest clarity and delight. Conversely, when they are in the lowest level they are in shadow and coolness, or in what is dim and unpleasant. From this latter state they return to the first, and so on. The phases follow each other with constant variety.
These states follow each other like variations of light and shade, warmth and cold, or like the morning, noon, evening, and night of individual days in our world, varying constantly throughout the year. Not only that, they correspond—morning to the state of their love in clarity, noon to the state of their wisdom in clarity, evening to the state of their wisdom in dimness, and night to a state of no love or wisdom. It should be known, though, that there is no correspondence of night with the states of life of people in heaven, but rather a correspondence of the half-light that comes before dawn. The correspondence of night is with people who are in hell.
Because of this correspondence, “day” and “year” in the Word mean states of life in general, warmth and light mean love and wisdom, morning the first and highest level of love, noon wisdom in its light, evening wisdom in its shade, and the half-light the dimness that comes just before the morning. Night, though, means the loss of love and wisdom.
from Heaven and Hell, Sections 154,155