The Initiation Rite

All who approached the Mystery at Eleusis, for example, were required to have certain knowledge and to undergo special rituals. The revelation of the Mystery “opened their eyes” and they were enlightened, but the exact nature of that mystical revelation was so secret that still, after some two-and-a-half thousand years, it remains unknown. We know that the worshipers purified themselves in the sea and made a ritual sacrifice to the Goddess Demeter, and that their journey to the Sanctuary was made with much ceremony, with dance and with the cry, “Iaccus!”. 

Enlightenment, which marked initiation, was different for each individual. But, in any case, a vow of secrecy protected the Divine Mystery. The same is true of many Cabbalistic, Hermetic, Alchemical and Magical associations, where to break the vow of secrecy is regarded (metaphorically) as the death of the initiate.