Shatapatha Brahmana 4.5.5.13

4.5.5.13

ekaṃ ha tveva tatpātram | yadimāḥ prajā anu prajāyanta upāṃśupātrameva prāṇo hyupāṃśuḥ prāṇo hi prajāpatiḥ prajāpatiṃ hyevedaṃ sarvamanu

But indeed there is only that one cup after which creatures are produced here, to wit, the Upâmsu cup; for the Upâmsu is breath, and Pragâpati is breath, and everything here is after Pragâpati.