Esoteric Lesson
Because during the time when human beings are outside their bodies, there is a longing within them, a strong urge to return to their physical bodies. This urge acts like a darkening against the brightness of the spiritual world, so that human beings perceive nothing of it. The astral forces at work within him are so strong that he would not leave his physical body at all if it were not so tired and worn out by life in the sensory world that it urgently needed the strengthening and refreshment provided by sleep. It is this urge, this longing for his physical body, that prevents man from consciously experiencing the spiritual worlds during sleep. If he were clairvoyant, he would see bright rays emanating from his astral body and ego toward his physical and etheric bodies; these rays express this longing for reunification.
Cite:
GA 266c/1914-04-25/p007 · edition English