The higher worlds are everywhere around us. These worlds are, however, not only paradisiacal worlds, not just worlds of bliss, although magnificence and happiness are there as well; but they are also worlds that can be terrible for people, dangerous because of actualities and creatures present there. If the human being wants to obtain knowledge of the magnitude and the blessings of these worlds, then he cannot avoid also meeting with the dangerous, with the frightful aspects that these worlds also contain. The one is not possible without the other.
Source (German): Rudolf Steiner – GA 56 – Die Erkenntnis der Seele und des Geistes – Berlin, December 12, 1907 (page 143-144)
Translated by Nesta Carsten-Krüger