Shatapatha Brahmana 7.5.1.30

7.5.1.30

dhruvāsi dharuṇeti | tasyokto bandhurito jajñe prathamamebhyo yonibhyo adhi jātavedā ityetebhyo hi yonibhyaḥ prathamaṃ jātavedā ajāyata sa gāyatryā triṣṭubhānuṣṭubhā ca devebhyo havyaṃ vahatu prajānannityetairvā eṣa candobhirdevebhyo havyaṃ vahati prajānan

[He sets the fire-pan down, with Vâg. S. XIII, 34-35] 'Steady thou art, supporting,' the meaning of this has been explained;--'from here he was at first born, from these wombs, the knower of beings;' for from these wombs the knower of beings (Agni) was indeed born at first;--'by the Gâyatrî, the Trishtubh, and the Anushtubh, may he, the knowing, bear the offering to the gods!'--by means of these metres he, the knowing, indeed bears the offering to the gods.