Śatapatha Brāhmaṇa ("of a hundred paths") 2.4.3.14

2.4.3.14

dvayā vai devā devāḥ | ahaiva devā atha ye brāhmaṇāḥ śuśruvāṃso 'nūcānāste manuṣyadevāstadyathā vaṣaṭkṛtaṃ hutamevamasyaitadbhavati tatro yacaknuyāttaddadyānnādakṣiṇāṃ haviḥ syāditi hyāhurnāgnihotre juhuyātsamadaṃ ha kuryādyadagnihotre juhuyādanyadvā āgrayaṇamanyadagnihotraṃ tasmānnāgnihotre juhuyāt

Verily, there are two kinds of gods: for the gods themselves, assuredly, are gods; and those priests who have studied, and teach Vedic lore, are the human gods. And in like manner as that is offered whereon the Vashat has been pronounced, so is that (offering of first-fruits consecrated by the feeding of the priests). Let him also, at this (sacrifice), give as much as is in his power, for no offering, they say, should be without a dakshinâ. At the Agnihotra (performed at the time of the Âgrayaneshti) let him not offer (milk obtained from the eating of new corn); for were he to offer such at the Agnihotra, he would cause a conflict (between the deities of the two offerings). The Âgrayana is one thing, and the Agnihotra is another: let him, therefore, not offer (new material) at the Agnihotra.