The Deeper Symbolism of Freemasonry from The Meaning of Masonry by Walter Leslie Wilmshurst.

“These Mysteries were formerly taught, we are told, ‘on the highest hills and in the lowest valleys,’ which is merely a figure of speech for saying, first, that they have been taught in circumstances of the greatest seclusion and secrecy, and secondly, that they have been taught in both advanced and simple forms according to the understanding of their disciples.” [via]

Consider also:

  1. “It is, of course, common knowledge that great secret systems of the Mysteries (referred to in, our lectures as ‘noble orders of architecture,’ i.e., of soul-building) existed in the East, in Chaldea, Assyria, Egypt, Greece, Italy, amongst the Hebrews, amongst Mahommedans and amongst Christians; even among uncivilized African races they are to be found. All the great teachers of humanity, Socrates, Plato, Pythagoras, Moses, Aristotle, Virgil, the author of the Homeric poems, and the great Greek tragedians, along with St. John, St. Paul and innumerable other great names–were initiates of the Sacred Mysteries.”
  2. “Hitherto, in his state of ignorance and moral blindness, the spiritual part of his nature has, as it were, but hovered above him; he has been unconscious of its presence in his constitution; but now, having realized its existence, the day-spring from on high has visited him, and the nobler part of him descends into his lower nature, illuminating and enriching it.”
  3. “Anyone, of course, can understand the simpler meaning of our symbols, especially with the help of the explanatory lectures; but he may still miss the meaning of the scheme as a vital whole.”
  4. “What is extremely ancient in Freemasonry is the spiritual doctrine concealed within the architectural phraseology; for this doctrine is an elementary form of the doctrine that has been taught in all ages, no matter in what garb it has been expressed.”
  5. Witch, Warlock, and Magician