Taittirīya Upaniṣad 2.3

2.3.1

prāṇaṃ devā anu prāṇanti /
manuṣyāḥ paśavaśca ye /
prāṇo hi bhūtānāmāyuḥ /
tasmāt sarvāyuṣamucyate /
sarvameva ta āyuryanti /
ye prāṇaṃ brahmopāsate /
prāṇo hi bhūtānāmāyuḥ /
tasmāt sarvāyuṣamucyata iti /
tasyaiṣa eva śārīra ātmā /
yaḥ pūrvasya /
tasmādvā etasmāt prāṇamayāt /
anyo 'ntara ātmā manomayaḥ /
tenaiṣa pūrṇaḥ /
sa vā eṣa puruṣavidha eva /
tasya puruṣavidhatām /
anvayaṃ puruṣavidhaḥ /
tasya yajureva śiraḥ /
ṛgdakṣiṇaḥ pakṣaḥ /
sāmottaraḥ pakṣaḥ /
ādeśa ātmā /
atharvāṅgirasaḥ pucchaṃ pratiṣṭhā /
tadapyeṣa śloko bhavati // 1//
iti tṛtīyo 'nuvākaḥ //

The gods do breathe along with breath (_prāṇa_),
As also men and beasts.
For truly, breath is the life (_āyus_) of beings.
Therefore it is called the Life-of-all (_sarvāyuṣa_).

To a full life (*sarvam āyus*) go they Who worship Brahma as breath. For truly, breath is the life of beings; Therefore it is called the Life-of-all.

This, indeed, is its bodily self (*śarīra-ātman*), as of the former.

Verily, other than and within that one that consists of breath is a self that consists of mind (*mano-maya*). By that this is filled. This, verily, has the form of a person. According to that one's personal form is this one with the form of a person. The Yajur-Veda is its head; the Rig-Veda, the right side; the Sāma-Veda, the left side; teaching, the body (*ātman*); the Hymns of the Atharvans and Aṅgirases, the lower part, the foundation.

As to that there is also this verse:—