Śatapatha Brāhmaṇa ("of a hundred paths") 4.3.4.20

4.3.4.20

athaivamupasadya | agnīdhe hiraṇyaṃ dadātyasmadrātā devatrā gacateti yāṃ vai rātamanā avicikitsandakṣiṇāṃ dadāti tayā mahajjayati devatrā gacateti devaloke me 'pyasaditi vai yajate yo yajate taddevaloka evainametadapitvinaṃ karoti pradātāramāviśateti māmāviśatetyevaitadāha tatho hāsmādetāḥ parācyo na praṇaśyanti tadyadagnīdhe prathamāya dakṣiṇāṃ dadātyato hi viśve devā amṛtatvamapājayaṃstasmādagnīdhe prathamāya dakṣiṇāṃ dadāti

Having thus respectfully sat down by the Agnîdh, he gives him the gold, with 'Given (râta) by us, go ye to the gods!'--for whatever sacrificial gift he gives unhesitatingly, with a liberal (râta) mind, thereby he gains great things, 'Go ye to the gods,' he says, for he who sacrifices, sacrifices with the hope, 'May there be a place for me in the world of the gods;' and he thus makes him a sharer in the world of the gods.--'Enter ye to the Giver!' whereby he means to say, 'Enter ye into me!' and thus those (cows) do not get lost to him. And as to his giving a dakshinâ first to the Agnîdh, it was from thence (from the Âgnîdhra) that all the gods gained immortality: therefore he gives the dakshinâ first to the Agnîdh.