Shatapatha Brahmana 3.2.2.12

3.2.2.12

tadvā ṛṣīṇāmanuśrutamāsa | te yajñaṃ samabharanyathāyaṃ yajñaḥ sambhṛta eṣa vā atra yajño bhavati yo dīkṣata eṣa hyenaṃ tanuta eṣa enaṃ janayati tadyadevātra yajñasya nirdhītaṃ yadvidugdhaṃ tadevaitatpunarāpyāyayati yadeṣa eva vratayati nāgnau juhoti na hāpyāyayedyadagnau juhuyājjuhvadu haiva manyeta nājuhvat

Now this was heard by the Rishis. They collected the sacrifice. As that sacrifice was collected, so does he who is consecrated now become the sacrifice, for it is he that carries it on, that produces it. And whatever (sap) of the sacrifice was sucked out and drained, that he now restores again by sipping the fast-milk and not offering it in the fire; for, assuredly, were he to offer it in the fire, he would not replenish (the sacrifice). But let him, nevertheless, think (that he does so) sacrificing and not the reverse.