The Two Marriages

Fire	actively	static
Air	actively	changing
Water	passively	changing
Earth	passively	static

That is to say, Osiris-Zeus and Set-Aidoneus are male because they act upon, while Isis-Hera and Nephthys-Nestis are female because they are acted upon. Osiris-Zeus and Isis-Hera are married and king/queen of the golden age because they are static; Set-Aidoneus and Nephthys-Nestis are married and always trying to topple and/or put back together the golden age because they are mutable.

Thus, without soul acting on bodies, they simply fall apart. With soul acting on them, they grow on their own, requiring no special effort. The higher mental faculties, however, require effort in order to grow and develop. Consciousness itself is already at its peak capacity and is ever-illuminating.

The goal of the Mysteries is to overcome Earth and Water, and so they enjoined silence on their followers in order to force them to make effort, because that is the only way one's Airy part can grow.