17. Śāṇḍilya Upaniṣad on OM

Meditating in a secluded place, the fluctuations of the mind are arrested through the right realization of the true nature of the sound which is at the extreme end of the pronounciation of the syllable OM (viz. Ardhamātra) and when Suṣupti (dreamless) sleeping state is rightly cognized through consciousness, the fluctuations of Prāṇa are repressed. When the passage at the root of the palace which is like the bell, viz Uvula is dosed by the tongue with effort and when the breath goes up through (the upper hole) then the fluctuations of Prāṇa are stopped. When the consciousness (samvit) is merged in Prāṇa and when through practice the Prāṇa goes through the upper hole into the dvādaśānta (the twelfth centre) above the palate, then the fluctuations of prāṇa are stopped. When the eye of consciousness (viz the spiritual or third eye) becomes calm and clear so as to be able to distinctly see in the transparent ākāśa at a distance of twelve digits from the tip of his nose, then the fluctuations of prāṇa are stopped.

When the thoughts arising in the mind are bound up in the calm contemplation of the world of tāraka (star or eye) between one’s eyebrows and are thus destroyed, then the fluctuations cease.

[...] Śāndilya Upaniṣad 34

When the knowledge which is of the form of the knowable, which is beneficent and which is untouched by any modification arises in one and is known as Om only and no other, the fluctuations of prāṇa cease. By the contemplation for a long time of the ākāśa which is in the heart, and by the contemplation of the mind free from vāsanas, then the fluctuations of prāṇa cease. By these methods and various others suggested by one’s thought and by means of the contact of the many (spiritual) guides, the fluctuations cease.^[1]

Footnotes and references:

[1]:

Śāndilya Upaniṣad verse 28-35.