Śatapatha Brāhmaṇa ("of a hundred paths") 4.3.1.22

4.3.1.22

yadvevaindrāgnaṃ grahaṃ gṛhṇāti | sarvaṃ vā idam prājījanadya ṛtugrahānagrahītsa idaṃ sarvam prajanayyedamevaitatsarvam prāṇodānayoḥ pratiṣṭhāpayati tadidaṃ sarvam prāṇodānayoḥ pratiṣṭhitamindrāgnī hi prāṇodānāvime hi dyāvāpṛthivī prāṇodānāvanayorhīdaṃ sarvam pratiṣṭhitam

And again, why he draws the Aindrâgna graha. By drawing the libations to the seasons he has generated this All, and having generated this All, he now establishes it on the out-breathing and in-breathing: hence this All is established on the out-breathing and in-breathing, for Indra and Agni are the out-breathing and in-breathing, and these two, heaven and earth, are the out-breathing and in-breathing, and within these two this All is established.