Śatapatha Brāhmaṇa ("of a hundred paths") 4.6.1.1

4.6.1.1

prajāpatirvā eṣa yadaṃśuḥ | so 'syaiṣa ātmaivātmā hyayam prajāpatistadasyaitamātmānaṃ kurvanti yatraitaṃ gṛhṇanti tasminnetānprāṇāndadhāti yathā yathaite prāṇā grahā vyākhyāyante sa ha sarvatanūreva yajamāno 'muṣmiṃloke sambhavati

Now, the Amsu (graha), forsooth, is no other than Pragâpati: that (cup) is his (Yagña's or the Sacrificer's) self, for Pragâpati is the self. Hence when they draw that (cup) they produce that self of his. Therein they lay these vital airs, according to as these vital airs, the grahas, are explained; and verily the sacrificer is born with his whole body in yonder world.