You will see that a man does not take with him into the world after death anything that lives in his physical and etheric bodies. That is thrown off and sinks away into the Cosmos. He takes with him only what as Ego and astral body he has experienced within his physical and etheric bodies.
Something of outstanding significance and importance follows from this. While a man is going about on Earth, he regards his physical body and his etheric body — of which he knows little, but at least he feels it in his powers of growth, and so on — as his own body, but he has no right to do so. Only his Ego and his astral body are his. Everything present in his physical body and etheric body — even while he is on Earth — is the property of the divine-spiritual Beings who live and weave within them, and continue their work while the man is absent in sleep.
It would go badly with anyone if he had to care for his own etheric and physical bodies in continual wakefulness between birth and death. Time and time again he is obliged to hand over his physical and etheric bodies to the Gods — especially during childhood, for then sleep is the most important thing of all. Later in life sleep works only as a corrective; the really fructifying sleep is the sleep that comes to a child in the first years of its life. Thus the human being has continually to be yielding up both physical and etheric bodies to the care of the Gods.
Source: Rudolf Steiner – GA 227 – The Evolution of Consciousness: Lecture X: Man’s Life after Death in the Spiritual Cosmos – August 28, 1923
Translated by Violet E. Watkin and Charles Davy