Incarnations do not repeat themselves in endless cycles; they had a beginning and will have an end. Once, in a far distant past, man did not descend to Earth for his incarnation. He then led a sort of angelic life, and birth and death were unknown to him. His life condition was uninterrupted by the present radical changes of birth and death. Just as surely, time is coming when man will not be forced to dive into the lower worlds again. This will come about when his sojourn in the lower worlds has enabled him to gather enough experience, and acquire a ripe and clear consciousness that is sufficient to allow him to work in the higher worlds.
Source (German): Rudolf Steiner – GA 108 – Die Beantwortung von Welt- und Lebensfragen durch Anthroposophie – Breslau, December 2, 1908 (page 61)