This is a small Upaniṣad belonging to the Atharvaveda. It is in prose. It is divided into three sections containing twenty mantras.
Three sages—Pippalāda, Aṅgiras and Sanatkumāra—approach the venerable Atharvaṇa and seek instructions from him on meditation. Atharvaṇa teaches them meditation on Om or Praṇava which is the best symbol for Brahman, both in its higher and in its lower aspects. The three parts of Om, viz., a, u and m, as also the last unseen part, are described as representing the various aspects and levels of creation. For instance, a represents the earth, the Ṛgveda, Brahmā and the deities known as Vasus. It also represents the gāyatrī metre and the gārhapatya fire. Similarly, u stands for the intervening space between the earth and heaven, the Yajurveda, Rudra, and the eleven subsi-diary deities also called Rudras, as also the triṣṭubh metre and the dakṣiṇa fire. The syllable m indicates heaven, the Sāmaveda, Viṣṇu, the deities called Ādityas, the jagatī metre and the āhavanīya fire. The last unseen half-syllable (‘ardhamātrā’) is the symbol of the Atharvaveda, the ‘saṁvartaka’ fire that destroys creation at the end of the cycle and the deities called Maruts.
Meditation on this Praṇava leads to liberation from rebirth.