Aitareya Āraṇyaka 2.2.3

2.2.3

viśvāmitraṃ hy etad ahaḥ śaṃsiṣyantam indra upaniṣasāda \
sa hānna/m ity abhivyāhṛtya bṛhatīsahasraṃ śaśaṃsa.
tenendrasya priyaṃ dhāmopeyāya \
tam indra uvāca.
ṛṣe priyaṃ vai me dhāmopāgāḥ.
sa vā ṛṣe dvitīyaṃ śaṃseti \
sa hānnam ity evābhivyāhṛtya bṛhatīsahasraṃ śaśaṃsa.
tenendrasya priyaṃ dhāmopeyāya \
tam indra uvāca.
ṛṣe priyaṃ vai me dhāmopāgāḥ.
sa vā ṛṣe tṛtīyaṃ śaṃseti \
sa hānnam ity evābhivyā/hṛtya bṛhatīsahasraṃ śaśaṃsa.
tenendrasya priyaṃ dhāmopeyāya \
tam indra uvāca.
ṛṣe priyaṃ vai me dhāmopāgā.
varaṃ te dadāmīti \
sa hovāca.
tvām eva jānīyām iti \
tam indra uvāca.
prāṇo vā aham asmy.
ṛṣe prāṇas tvaṃ.
prāṇaḥ sarvāṇi bhūtāni.
prāṇo hy eṣa, ya eṣa tapati.
sa etena rūpeṇa sarvā diśo viṣṭo 'smi.
tasya me 'nnaṃ mitraṃ dakṣiṇaṃ.
tad vaiśvāmitram.
eṣa tapann evāsmīti hovāca \\ 3 \\

While Visvâmitra was going to repeat the hymns of this day (the mahâvrata), Indra sat down near him. Visvâmitra (guessing that Indra wanted food) said to him, 'This (the verses of the hymn) is food,' and repeated the thousand Brihatî verses By means of this he went to the delightful home of Indra (Svarga).

Indra said to him: 'Rishi, thou hast come to my delightful home. Rishi, repeat a second hymn.' Visvâmitra (guessing that Indra wanted food) said to him, 'This (the verses of the hymn) is food,' and repeated the thousand Brihatî verses. By means of this he went to the delightful home of Indra (Svarga).

Indra said to him: 'Rishi, thou hast come to my delightful home. Rishi, repeat a third hymn.' Visvâmitra (guessing that Indra wanted food) said to him, 'This (the verses of the hymn) is food,' and repeated the thousand Brihatî verses. By means of this he went to the delightful home of Indra (Svarga).

Indra said to him: 'Rishi, thou hast come to my delightful home. I grant thee a boon.' Visvâmitra said: 'May I know thee.' Indra said: 'I am Prâna (breath), O Rishi, thou art Prâna, all things are Prâna. For it is Prâna who shines as the sun, and I here pervade all regions under that form. This food of mine (the hymn) is my friend and my support (dakshina). This is the food prepared by Visvâmitra. I am verily he who shines (the sun).'