Retrace consciousness
When we enter relative awareness through sound expansion, we can also reenter transcendent consciousness through the willful contractions of sound that occur in meditation. Tracing OM̐ back to the source, the meditator finds it in himself as Power and Mindfulness, experiencing the subtle state of OM̐ and the subtle consciousness inherent in OM̐.
The self, although hidden in all beings, does not shine but can be seen by those subtle seers, through their sharp and subtle intellect. The wise must hold words to mind; lastly he must refrain into understanding the Self. The self that understands one must hold back in the great self. That he should restrain himself to a quiet self – Katha Upanishad 1.3.12,13.
What is meant by mind is manas (sensory thought); what is meant by “understanding oneself is buddhi (intellect); what is meant by “the great Self” is desire; and by “self-tranquility” defined as the most subtle level, Chidakasha, the witness relationship between pure consciousness and our perceptions.
In Viveka Chudamani (verse 369) Shankar a puts it this way :
Withholding speech in manas, and restraining mana in buddhi; this again holds back in the testimony of buddhi (Chidakasha), and incorporates it also in the Infinite Absolute Self, attaining Supreme Peace.
The Brihadaranyaka Upanishad tells us:
The ability to speak is a place of amalgamation
In the subtle sound OM̐, a yogi’s consciousness is cut off into a pure and holy state.
Oneness of Breath and OM̐
As already quoted, commenting on the Yoga Sutras, Vivekananda said:
The whole universe is a combination of prana and akasha.
Practically we are also formed from prana and akasha , the breath and sound which are manifestations of prana and akasha. Yoga is a combination of breath and sound. OM̐ is a form of essential sound energy which manifests in the living entity as the breath itself. OM̐ is the sound form of the subtle life force that comes from the pure consciousness, the soul, of each of us and extends outward to manifest as the inhaling breath and the exhaling breath.
The breath continues to sound ‘Om’ – Chandogya Upanishad 1.5.3
Therefore, through chanting OM̐ in meditation, we can become in tune with the Essential Breath of Life and become aware of its subtle movements within. Together with our breath, the OM̐ mantra formula will bring us to the consciousness of Breath and Life in their pure state. Because OM̐ is the breath and the Source of breath. On joining OM̐, the breath becomes a flowing stream of consciousness.