Śatapatha Brāhmaṇa ("of a hundred paths") 9.1.2.17

9.1.2.17

yadveveṣṭakā dhenūḥ kurute | vāgvā ayamagnirvācā hi citaḥ sa yadāhaikā ca daśa cāntaśca parārdhaśceti vāgvā ekā vāgdaśa vāganto vākparārdho vācameva taddevā dhenumakurvata tathaivaitadyajamāno vācameva dhenuṃ kurute 'tha yatsaṃtanoti vācameva tatsaṃtanotyetā me agna iṣṭakā dhenavaḥ santvamutrāmuṣmiṃloka ityetadvā enā asmiṃloke dhenūḥ kurute 'thainā etadamuṣmiṃloke dhenūḥ kurute tatho hainametā ubhayorlokayorbhuñjantyasmiṃścāmuṣmiṃśca

And as to why he makes the bricks his own milch cows,--this fire-altar is speech, for with speech it is built up; and when he says, 'One, and ten,... and a hundred thousand millions, and a billion,'--'one' is speech, and a hundred thousand millions is speech, and a billion is speech: it is Speech herself that the gods thereby made their own milch cow; and in like manner does the Sacrificer thereby make Speech herself his own milch cow. And in that he carries on (the numbers) uninterruptedly, thereby it is Speech herself that he carries on:--'Let these bricks be mine own milch cows, O Agni, hereafter in yonder world!' He thereby makes them his own milch cows in this world, and he also makes them his own milch cows in yonder world; and thus they are profitable to him in both worlds, in this one and in the other.