Śatapatha Brāhmaṇa ("of a hundred paths") 4.1.2.27

4.1.2.27

iyaṃ ha vā upāṃśuḥ | prāṇo hyupāṃśurimāṃ hyeva prāṇannabhiprāṇityasāvevāntaryāma udāno hyantaryāmo 'muṃ hyeva lokamudanannabhyudanityantarikṣamevopāṃśusavano vyāno hyupāṃśusavano 'ntarikṣaṃ hyeva vyanannabhivyaniti

The Upâmsu, forsooth, is this (earth), for the Upâmsu is the out-breathing, and breathing out one breathes upon this (earth). And the Antaryâma is yonder (sky), for the Upâmsu is the in-breathing (up-breathing), and in breathing up one breathes towards yonder world. And the Upâmsu-savana (stone) is the air, for the Upâmsu-savana is the through-breathing, and he who breathes through (in and out), breathes through this air.