Mandukya Upanishad

1. 1The sacred sound Om stands for everything that exists. Past, present and future are all Om, and so is whatever lies beyond time itself.
2. 2Everything is Brahman, the one ultimate reality, and your own true self (atman) is that same Brahman. This self can be understood in four parts, or states.
3. 3The first state of the self is being awake. In this state we know the outside world through the body and senses and experience solid physical things. This waking self is called Vaishvanara, meaning the one shared by all people.
4. 4The second state of the self is dreaming. Here the mind turns inward and experiences subtle, delicate things. This dreaming self is called Taijasa, meaning the bright or shining one.
5. 5The third state is deep, dreamless sleep, when we want nothing and see no dreams. Here awareness is gathered into one, peaceful and full of bliss. This self is called Prajna, the knowing one.
6. 6This deep-sleep self is the lord of all, knows all, and guides everything from within. All beings come from it and return to it in the end.
7. 7The fourth state is beyond waking, dreaming and deep sleep. It cannot be seen, grasped, thought about or described in words; it is pure peace, goodness and oneness with nothing separate from it. This is the true Self, and we should come to know it.
8. 8The Self can also be understood through the sound Om. Om has three sounds, A, U and M, and these match the parts of the Self.
9. 9The sound A stands for the waking state, because A comes first and suggests reaching or obtaining. Whoever understands this gets what they wish for and becomes first.
10. 10The sound U stands for the dreaming state, because it is in the middle and suggests rising up. Whoever understands this grows in knowledge, becomes balanced with all, and their family will not lack knowledge of Brahman, the ultimate reality.
11. 11The sound M stands for deep sleep, because it suggests both building up and merging back. Whoever understands this builds up the whole world and becomes the place where it all merges back.
12. 12The fourth state has no sound part of its own; it cannot be dealt with, it is where all change stops, it is good and has no second. Om is truly the Self, and whoever knows this merges their own self into the highest Self.