For in penetrating to the higher mysteries he will see things which are concealed from ordinary humanity by the illusion of the senses. If the physical senses do not allow us to perceive the higher truth, they are for this very reason our benefactors. Things are thereby hidden from us which, if realized without due preparation, would throw us into unutterable consternation, and the sight of which would be unendurable.

Rudolf Steiner, How to Know Higher Worlds [Amazon, Bookshop, Publisher, Local Library]

Hermetic quote Steiner How to Know Higher Worlds higher mysteries concealed ordinary humanity illusion senses truth hidden without preparation unutterable unendurable