Śatapatha Brāhmaṇa ("of a hundred paths") 7.2.3.6

7.2.3.6

yadvevainamabhijuhoti | etadvai yānyetasminnagnau rūpāṇyupadhāsyanbhavati yāntstomānyāni pṛṣṭhāni yāni candāṃsi tebhya etam purastādbhāgaṃ karoti tānyevaitatprīṇānyājyena pañcagṛhītena tasyokto bandhuḥ

And, again, why he offers thereon;--whatever forms, whatever modes of chanting, whatever prishtha (stotras), whatever metres he is now going to bestow on Agni, for them he prepares this fore-share, and it is them he thereby gratifies. With fivefold-taken ghee (he offers): the significance of this has been explained.