Śatapatha Brāhmaṇa ("of a hundred paths") 7.1.2.14

7.1.2.14

atha yadantarāhavanīyaṃ ca gārhapatyaṃ ca | sa ātmātha ya āgnīdhrīye 'gnirya evāyamantarātmanprāṇaḥ so 'sya sa pratiṣṭhaivāsya gārhapatyo 'tha yo gārhapatye 'gniḥ so 'syāvāṅ prāṇaḥ

And what space there is between the Âhavanîya and Gârhapatya, that is the body (trunk); and the fire on the Âgnîdhrîya is to him that vital air inside the body. The Gârhapatya is his foundation; and the fire on the Gârhapatya is his downward vital air.