Aitareya Āraṇyaka 2.2.4

2.2.4

tad vā idaṃ bṛhatīsahasraṃ saṃpannaṃ.
tasya tāni vyañjanāni tac cha/rīraṃ.
yo ghoṣaḥ, sa ātmā.
ya ūṣmāṇaḥ, sa prāṇaḥ \
etad dha sma vai tad vidvān vasiṣṭho vasiṣṭho babhūva.
tata etan nāmadheyaṃ lebhe \
etad u haivendro viśvāmitrāya provāca-.
etad u haivendro bharadvājāya provāca.
tasmāt sa tena bandhunā yajñeṣu hūyate \
tad vā idaṃ bṛhatīsahasraṃ saṃpannam.
tasya vā etasya bṛhatīsahasrasya saṃpannasya ṣaṭtriṃśatam akṣarāṇāṃ sahasrāṇi bhavanti.
tāvanti śatasaṃvatsarasyāhnāṃ sahasrāṇi bhavanti.
vyañjanair eva rātrīr āpnuvanti, svarair ahāni \
tad vā idaṃ bṛhatīsahasraṃ saṃpannaṃ.
tasya vā etasya bṛhatīsahasrasya saṃpannasya parastāt pra/jñāmayo devatāmayo brahmamayo 'mṛtamayaḥ saṃbhūya devatā apyeti, ya evaṃ veda \
tad yo 'haṃ, so 'sau.
yo 'sau, so 'ham \
tad uktam ṛṣiṇā \
sūrya ātmā jagatas tasthuṣaś ca- (RV I 115,1d) -iti \
etad u haivopekṣetopekṣeta \\ 4 \\
ity aitareyadvitīyāraṇyake dvitīyo 'dhyāyaḥ \\

This then becomes perfect as a thousand of Brihatî verses. Its consonants form its body, its voice (vowels) the Soul, its sibilants the air of the breath.

He who knew this became Vasishtha, he took this name from thence.

Indra verily declared this to Visvâmitra, and Indra verily declared this to Bharadvâga. Therefore Indra is invoked by him as a friend.

This becomes perfect as a thousand of Brihatî verses, and of that hymn perfect with a thousand Brihad verses, there are 36,000 syllables. So many are also the thousands of days of a hundred years (36,000). With the consonants they fill the nights, with the vowels the days.

This becomes perfect as a thousand of Brihatî verses. He who knows this, after this thousand of Brihatîs thus accomplished, becomes full of knowledge, full of the gods, full of Brahman, full of the immortal, and then goes also to the gods.

What I am (the worshipper), that is he (sun); what he is, that am I.

This has been said by a Rishi (Rv. I, 115, 1): 'The sun is the self of all that moves and rests.'

Let him look to that, let him look to that!