What are the keys that are present in the Christian, Zoroastrian, and Roman religion(s)?
Matthew 16:19 speaks of Jesus giving the keys of the kingdom of heaven to St. Peter.
Revelation 1:18 speaks of Jesus (or God) that he has the keys of hell and death.
Janus, the Roman god of time, duality, etc., was often depicted with a key in his hand.
http://1.bp.blogspot.com/--BhTJIqW4uA/U ... /janus.gif
I got the picture from:
http://artjewelryelements.blogspot.com/ ... d-key.html
Zurvan, the Zurvan Zoroastrian supreme deity of Time, has the "Keys of Time".
Sources:
Symbol Dictionary - Keys of St. Peter:
http://symboldictionary.net/?p=2954
Wikipedia - Janus:
http://en.wikipedia.org/wiki/Janus
Encyclopedia Britannica - Zurvan (ancient god):
http://www.britannica.com/EBchecked/topic/658515/Zurvan
The Bible talks of two keys (as already mentioned): the keys of the kingdom of heaven, and the keys of hell and death (the Hebrew word for hell, "sheoul", is equated with death). In Luke 17:21, Jesus says that the kingdom is "within you". By "within you", it can either mean within the Heart, which is commonly symbolized as Love, or it can be the Mind, which means Intellect and Knowing. Or it could be some "primordial essence", or primordial energy, which permeates both mind and heart.
So if we were to connect the keys of heaven or hell, we could say that heaven and hell represent the depths of consciousness/unconsciousness (speaking of mind), and/or the depths of the karma and emotions inside the heart. Revelation is about, in a metaphysical sense, the trials that the soul (or existence) goes through in order to reach heavenly perfection. Enlightenment requires people to go through their individual "Hall of Records" (the memories inside the consciousness of the brain), in order to have a perfect mind. Having pure love means to go through the past karmic misadventures to find pure love in the heart (which is often why people shed tears when reminded of the troubles).
The keys can also mean the keys of reality, such as in Janus and Zurvan. Zurvan, the chief god of ancient Persia, is represented as a serpent, and represents time. The symbolism of the serpent will be discussed in the future, but the serpent, in the Hindu Tantric sense, is the shakti (feminine energy) that brings enlightenment to people when awakened. So that would mean that awakening the Kundalini can be equivalent of possibly unlocking the secrets of Zurvan. This goes back to the path of Enlightenment that was talked of in the last paragraph.
So what is the key itself? My guess would be that the key could be the authority or privilege to see the hidden; could also be the force of the individual that is used to find this knowledge.