MANDUKYA UPANISHAD
OM. This eternal Word is all: what was, what is and what shall be, and what beyond is in eternity. All is OM.
Brahman is all and Atman is Brahman. Atman, the Self, has four conditions.
The first condition is the waking life of outward-moving consciousness, enjoying the seven outer gross elements.
The second condition is the dreaming life of inner-moving consciousness, enjoying the seven subtle inner elements in its own light and solitude.
The third condition is the sleeping life of silent consciousness when a person has no desires and beholds no dreams. That condition of deep sleep is one of oneness, a mass of silent consciousness made of peace and enjoying peace.
This silent consciousness is all-powerful, all-knowing, the inner ruler, the source of all, the beginning and end of all beings.
The fourth condition is Atman in his own pure state: the awakened life of supreme consciousness. It is neither outer nor inner consciousness, neither semi-consciousness, nor sleeping-consciousness, neither consciousness nor unconsciousness. He is Atman, the Spirit himself, that cannot be seen or touched, that is above all distinction, beyond thought and ineffable. In the union with him is the supreme proof of his reality. He is the end of evolution and non-duality. He is peace and love.
This Atman is the eternal Word OM. Its three sounds, A, U, and M, are the first three states of consciousness, and these three states are the three sounds.
The first sound A is the first state of waking consciousness, common to all men. It is found in the words Apti, ‘attaining’, and Adimatvam, ‘being first’. Who knows this attains in truth all his desires, and in all things become first.
The second sound U is the second state of dreaming consciousness. It is found in the words Utkarsha, ‘uprising’, and Ubhayatvaom, ‘bothness’. Who knows this raises the tradition of knowledge and attains equilibrium. In his family is never born any one who knows not Brahman.
The third sound M is the third state of sleeping consciousness. It is found in the words Miti, ‘measure’, and in the root Mi, ‘to end’, that gives Apiti, ‘final end’. Who knows this measures all with his mind and attains the final End.
The word OM as one sound is the fourth state of supreme consciousness. It is beyond the senses and is the end of evolution. It is non-duality and love. He goes with his self to the supreme Self who knows this, who knows this.