One who, knowing thus, meditates on the syllable (Om), by that (practice) attains the Ātman. The sage, therefore, becomes omniscient, becomes all. On this there is a verse:

This verse concludes the answer to the fifth question, on meditation on Om, revealing its supreme fruit.

Evaṃ vidvān — knowing thus. Prior knowledge is essential: Om is not a magical mantra that works automatically. It must be meditated upon with understanding of its meaning: the three sounds (A-U-M), the three states of consciousness, the three aspects of Brahman.

Akṣaraṃ praṇauti — meditates on the syllable. Akṣara means both “syllable” and “the imperishable”. Om is the imperishable syllable, the sound symbol of Brahman. Praṇauti (from praṇu, to meditate with devotion) indicates a deep contemplative practice, not mere mechanical repetition.

Tenaiṣa ātmānaṃ gamayati — by that one attains the Ātman. Meditation on Om is a vehicle (yāna) toward the Self. Sound leads beyond sound, toward the silence that precedes and follows it.

Sarvajñaḥ bhavati — becomes omniscient. Not in the sense of knowing all the data of the universe, but of knowing the Knower, that by which all knowledge is possible. To know the source is to know all.

Sarvo bhavati — becomes all. This is non-dual realization: the meditator discovers there is no separation between themselves and totality. The individual jīva recognizes itself as universal Brahman.

The practice of meditation on Om (praṇava-upāsanā) is thus one of the most direct methods toward liberation, mentioned in almost all major Upaniṣads and taken up again in Patañjali’s Yoga Sūtras.