"What were the greatest secrets that the successful candidates learned in the Mysteries ?"That depended on the degree through which they passed, but all their experiences could roughly be condensed into two results, which formed the core of the revelations they received.
"In the earlier degrees, the candidates were made acquainted with the human soul, pictured as a little bird-man in the system of hieroglyphs; they solved the mystery of death. They learned that it was really disappearance from one state of being, only to reappear in another; that it affected the fleshly body, but did not destroy the mind and the [Higher] self. They learned, too, that the soul not only survived the destruction of its mortal envelope but progressed onwards to higher spheres.
"In the advanced degrees, they were made acquainted with the divine soul; they were brought into personal communion with the Creator; they stood face to face with the Divine. They were first instructed in the true explanation of the Fall of Man from his original spiritual state. They were told the inner history of Atlantis, a history so intimately associated with the history of the Fall. Then they were lifted up, sphere beyond sphere, until they found themselves in the same highly spiritual consciousness as Man had enjoyed at the beginning. Thus, while yet on their pilgrimage in time, they had gathered the spoils of eternity."