Śatapatha Brāhmaṇa ("of a hundred paths") 10.5.4.8

10.5.4.8

tasyai vā etasyai ṣaṭtriṃśadakṣarāyai bṛhatyai yāni daśa prathamānyakṣarāṇi sā daśākṣaraikapadātha yāni viṃśatiḥ sā viṃśatyakṣarā dvipadātha yāni triṃśatsā triṃśadakṣarā virāḍatha yāni trayastriṃśatsā trayastriṃśadakṣarātha yāni catustriṃśatsā catustriṃśadakṣarā svarāḍatha yatsarvaiścandobhirayamagniścitastadaticandāstā u sarvā iṣṭakā eveṣṭaketi trīṇyakṣarāṇi tripadā gāyatrī tenaiṣa gāyatro'gnirmṛdāpa iti trīṇyakṣarāṇi tripadā gāyatrī teno evaiṣa gāyatro'tha yadantarā candasī tatsūdadohā atha yaccandaḥsvannaṃ tatpurīṣaṃ tā āhutayastāḥ samidho'tha yaccandāṃsītyākhyāyate tallokampṛṇā tadvā etatsarvaṃ candāṃsītyevākhyāyate tatsarvo'gnirlo

Now the first ten syllables of this Brihatî, consisting of thirty-six syllables, make an Ekapadâ of ten syllables; and the (first) twenty make a Dvipadâ of twenty syllables; and the (first) thirty a Virâg of thirty syllables; and the (first) thirty-three a (Virâg) of thirty-three syllables; and the (first) thirty-four a Svarâg of thirty-four syllables; and in that this fire-altar is built with all metres thereby it is an Atikhandas, and (so) indeed are all these bricks. And the three syllables 'ishtakâ (brick)' are a Gâyatrî tripadâ, whence this Agni is Gâyatra; and the three syllables 'mrid' (clay) and 'âpah' (water) also are a Gâyatrî tripadâ: thereby also he is Gâyatra. And what is between (each two) metres is the Sûdadohas; and the food which is in the metres is the earth-fillings, the oblations, and the fire-logs; and what is called 'metres,' that is the space-filling (brick):--thus this comes to make up the whole Agni; and the whole Agni comes to be the space-filler; and, verily, whosoever knows this, comes to be that whole (Agni) who is the space-filler.