In the beginning there was the unmanifest Absolute. In this nothingness, Consciousness stirred of its own accord and a sound arose – Om. Its vibrations rippled outwards creating Space and Time and the Universe was born.
Everything, the Vedas say, begins with Om and comes to rest in Om.
Mandukya Upanishad begins with this beautiful declaration-
Om ityetadaksharam idam sarvam,
tasyopavyakhyanam bhutam bhavat bhavishyaditi
sarvam omkara eva.
OM is the imperishable Word. OM is the Universe.
The past, the present and the future. All that was, all that is, all that will be, is OM.
Likewise, all else that may exist beyond the bounds of Time, that too is OM.
Om is the namarupa (name form) of the Absolute. It is pranava, the source, the very breath of all mantras. It is the beej mantra, the seed that lies within all mantras.
Om is both the Self and the way to know the Self. Hence the yogis meditate upon it, focusing on its three syllables AUM.
The letter A symbolises the conscious or waking state, the letter U is the dream state and the letter M is the dreamless sleep state of the mind and spirit. The entire symbol, together with the crescent and the dot, stands for the fourth state which combines all these states and transcends them. This is the state of samadhi or super consciousness.