Śatapatha Brāhmaṇa ("of a hundred paths") 6.6.4.6

6.6.4.6

sa vai samidhamādhāyātha vratayati | daivo vā asyaiṣa ātmā mānuṣo 'yaṃ devā u vā agre 'tha manuṣyāstasmātsamidhamādhāyātha vratayati

And having put on the kindling-stick, he drinks the fast-milk; for that (fire) is his divine body, and this (body of his) is the human one; and the gods (come) first, and then men: hence he drinks the fast-milk after putting the kindling-stick on (the fire).