"Know then, O thou who wishest to be initiated into the great mysteries, that thou makest a pact with suffering and encounterest Hell. The vulture which gorged itself on Prometheus’ entrails has fixed eye upon thee. And the Furies, lead by Mercury, are preparing the blocks of wood and nails. Thou shalt be sacred; that is to say, consecrated to torment. Humanity has need of thine agonies."

—  Eliphas Levi, The Great Secret

“Behind the veil of all the hieratic and mystical allegories of ancient doctrines, behind the darkness and strange ordeals of all initiations, under the seal of all sacred writings, in the ruins of Nineveh or Thebes, on the crumbling stones of old temples and on the blackened visage of the Assyrian or Egyptian sphinx, in the monstrous or marvelous paintings which interpret to the faithful of India the inspired pages of the Vedas, in the cryptic emblems of our old books on alchemy, in the ceremonies practiced at reception by all secret societies, there are found indications of a doctrine which is everywhere the same and everywhere carefully concealed.” 

- Eliphas Levi in the Introduction to his 'Dogma et Rituel de la Haute Magie' (Transcendental Magic, its Doctrine and Ritual, circa. 1855 A.D.)