Darkness Into Light
Why are humans so hard to understand?
Why are there some people who are "devils" and some who are clearly "angels"?
How can extremely good people have hidden dark sides?
To begin to reach some understanding, check out this remarkable quote from Reality:
"Man is in the highest degree of materiality, and at the beginning of spirituality—that is to say, he is the end of imperfection and the beginning of perfection. He is at the last degree of darkness, and at the beginning of light; that is why it has been said that the condition of man is the end of the night and the beginning of day, meaning that he is the sum of all the degrees of imperfection, and that he possesses the degrees of perfection. He has the animal side as well as the angelic side, and the aim of an educator is to so train human souls that their angelic aspect may overcome their animal side. Then if the divine power in man, which is his essential perfection, overcomes the satanic power, which is absolute imperfection, he becomes the most excellent among the creatures; but if the satanic power overcomes the divine power, he becomes the lowest of the creatures. That is why he is the end of imperfection and the beginning of perfection. Not in any other of the species in the world of existence is there such a difference, contrast, contradiction and opposition as in the species of man."
Man and His Progress after Death", pp. 235-236
