That part of the astral body which has been worked into the etheric body as rhythm is immortal

  

Rudolf Steiner:  "In Devachan man looks into himself. He observes what he has taken in. He must observe this for as long as is needed for it to reach a rhythmical condition. A stroke calls forth a counter-stroke; but only through many intermediate happenings does the counter-stroke return. The effect, however, persists during the intervening period. The interrelationship between stroke and counter-storke is worked over in Devachan and transformed into wisdom. What has been worked over and transformed into wisdom is metamorphosed in man into rhythm, in contradistinction to activity. What has been changed into rhythm passes over into the etheric body. After Devachan one has become wiser and better because in Devachan all experiences have been worked over. That part of the astral body which has been worked into the etheric body as rhythm is immortal."

 

Foundations of Esotericism, lecture 2, 9/27/1905