Śatapatha Brāhmaṇa ("of a hundred paths") 2.2.3.21

2.2.3.21

varuṇo hainadrājyakāma ādadhe | sa rājyamagacattasmādyaśca vada yaśca na varuṇo rājetyevāhuḥ somo yaśaskāmaḥ sa yaśo 'bhavattasmādyaśca some labhate yaśca nobhāvevāgacato yaśa evaitaddraṣṭumāgacanti yaśo ha bhavati rājyaṃ gacati ya evaṃ vidvānādhatte

He (the Adhvaryu) then says, with regard to Agni's (first) butter-portion, 'Pronounce the invitatory prayer to Agni!' He (the Hotri) recites, 'Awake Agni with praise, enkindling the immortal, that he may take our offerings to the gods!' For, indeed, when Agni is removed (from the hearth), he, as it were, sleeps: he (the priest) now awakens, rouses him. For the offering-prayer he recites, 'May Agni graciously accept of the butter!'