Śatapatha Brāhmaṇa ("of a hundred paths") 7.4.2.34

7.4.2.34

yadvevāṣāḍhāmupadadhāti | vāgvā aṣāḍhā vācaiva taddaivā asurāntsapatnānbhrātṛvyānasmātsarvasmādasahanta tathaivaitadyajamāno vācaiva dviṣantam bhrātṛvyamasmātsarvasmātsahate vācameva taddevā upādadhata tathaivaitadyajamāno vācamevopadhatte

And, again, why he lays down the Ashâdhâ. The Ashâdhâ is speech, and by speech the gods then indeed conquered (and drove) the Asuras, the enemies, the rivals, from this universe; and in like manner the Sacrificer, by means of speech, conquers (and drives) his spiteful rival from this universe: it was speech the gods then laid down (or bestowed on Agni), and in like manner the Sacrificer now lays down speech.