Śatapatha Brāhmaṇa ("of a hundred paths") 7.1.2.4

7.1.2.4

te 'bruvan | annaṃ vā ayam prajāpatistvanmukhā etadannamadāma tvanmukhānāṃ na eṣo 'nnamasaditi tatheti tasmāddevā agnimukhā annamadanti yasyai hi kasyai ca devatāyai juhvatyagnāveva juhvatyagnimukhā hi taddevā annamakurvata

They spake, 'This Pragâpati is food: with thee for our mouth we will eat that food, and he (Pragâpati) shall be the food of us, having thee for our month.' He said, 'So be it!' Therefore the gods eat food with Agni as their mouth; for to whatsoever deity men offer, it is into Agni that they offer, since it is with Agni for their mouth that the gods thus took in the food.