All final spiritual reference is to be the silence beyond sound. The word made flesh is the first sound. Beyond that sound is the transcendent unknown, the unknowable. It can be spoken of as the great silence, or as the void, or as the transcendent absolute.
There are two silences. One silence I choose to keep when I need to hear a word that will heal, instruct, or console. The other silence comes when I have heard something so powerful, so real, that words, spoken or written, would only diminish its power.