Yoga Sutra - Samādhi Pada 1.27
तस्य वाचकः प्रणवः ॥२७॥
tasya vācakaḥ praṇavaḥ ||27||
Its expression is pranava (OM).
The name designating him is the mystical syllable oṁ.
Patañjali states here that Īśvara is represented by the mystical syllable oṁ referred to here by its synonym, praṇavaḥ. Oṁ has been understood as a sonal incarnation of Brahman (which is the most common term used for the Absolute Truth in the Upaniṣads) since the late Vedic period.177 The Taittirīya Upaniṣad, for example, states: “Brahman is oṁ, this whole world is oṁ” (I.8.1), as does the Kaṭha Upaniṣad (II.16), the Praśna Upaniṣad (V.2–5), and the Māṇḍūkya Upaniṣad, which concerns itself entirely with the relation of manifest reality with this syllable. The Muṇḍaka Upaniṣad describes oṁ as the bow, the self as the arrow, and Brahman as the target that must be struck, paralleling Patañjali’s statement in the next sūtra. The Śvetāśvatara Upaniṣad states that through the practice (abhyāsa) of meditating on oṁ, one “can see God” (I.14).178 A scholastic such as Patañjali would most certainly have been well schooled in the Upaniṣads (especially given his own mandate of the prerequisite of study for success in yoga, II.1 and 44), which, as an orthodox thinker, he would have accepted as śruti, divine revelation. Even though he never refers to Brahman in the sūtras, here again we must allow for the possibility that, along with texts such as the Gītā,179 the Śvetāśvatara Upaniṣad, the epic, and the theologies of the Purāṇas—indeed, along with all the Īśvara theologies of his time, to my knowledge—he is consciously equating the Upaniṣadic Brahman with this personal Īśvara, by means of this common denominator of oṁ.
Vyāsa raises the question, which touches upon various Indian theories of language, of whether the relationship between the person Īśvara and the designation (vācaka) oṁ is conventional—a socially agreed upon usage—or inherent and eternal. The relationship of word and meaning (signifier and object signified) has an extensive history in Indian intellectual thought. Briefly, from conventional perspectives, “elephant” refers to a particular type of creature, but “camel” (or any other term, such as “abracadabra”) would do just as well provided it becomes a designation for this creature agreed upon by the speakers of the language. Different languages use different terms for the same object. The term “elephant” is thus conventional; it does not have an eternal or absolutely binding relationship with its referent. The same obviously holds true for personal names given to people, as Vijñānabhikṣu notes: The name Devadatta is given adventitiously to a son by his father—he could just as well have called him Viṣṇupriya.
An inherent relationship, on the other hand, is eternal and not dependent on social usage. Vyāsa gives the example of the relationship between a lamp and light; wherever there is a lamp there must always and necessarily be light. Such is the relationship between Īśvara and oṁ; it is not a culturally agreed upon designation. Īśvara was known by the syllable oṁ in previous creations, and will be for all eternity; it is an eternal designation not assigned by human convention or socially agreed upon usage (we will further explore the yoga understanding of language in general in III.17).
How can this be? wonders Vācaspati Miśra. After all, oṁ is just a sound and merges back into prakṛti along with all other sounds and all material objects at the dissolution of the universe, and its powers must thereby disappear. At a new creation, how can this particular phoneme regain its power from the previous creation? It remanifests with all its previous power, he continues, just like life-forms that disappear into the earth during the dry season burst back into the same life-forms after the rains. This particular and specific phoneme is eternally invested by Īśvara with his power. One can conclude, then, that not being subject to Time, Īśvara is not subject to cyclical creation and therefore can invest his potency eternally into the sacred syllable oṁ.