Jaiminīya (Talavakāra) Brāhmaṇa 53.281

53.281

gāyatramukho vai prathamastriyahaḥ
tasmādayamagnirūrdhvo dīdāya
gāyatramadhyo dvitīyastriyahaḥ
tasmādayaṃ vāyustiryaṅpavate
gāyatrottamastṛtīyastriyahaḥ
tasmādasāvarvāṅādityastapati
devāsurā aspardhanta
te'bruvanyo nastriranavānaṃ gāyatra gāyati sa na imāṃśca lokānsaṃjayati
prāṇāpānavyānāṃśceti
so'yāsya āṅgirasastriranavānaṃ gāyatramagāyat
tenemāṃśca lokānsamajayatprāṇāpānavyānāṃśca
saṃ imāṃśca lokāñjayati prāṇāpānavyānāṃśca ya evaṃ vidvāṃstriranavānaṃ gāyatraṃ
gāyati
yo vā agniṣṭomena daśāhaṃ kalpamānaṃ veda kalpate'smai prātassavanenaiva
prathamastryahaḥ | kalpate mādhyandinena dvitīyas | tṛtīyasavanena
tṛtīyo'gniṣṭomasāmnaiva daśamamahaḥ kalpate
kalpate'smai ya evaṃ veda

The first three-day period has the Gāyatrī at the beginning: therefore this fire burns upright. The second three-day period has the Gāyatrī in the middle: therefore this wind blows horizontally. The third three-day period has the Gāyatrī at the end: therefore that sun yonder shines downward. The gods and the asuras contended. They said: 'Whichever of us sings the Gāyatrī thrice without taking breath, he shall conquer both these worlds and the out-breath, down-breath, and through-breath.' Ayāsya Āṅgirasa sang the Gāyatrī thrice without taking breath. Thereby he conquered both these worlds and the out-breath, down-breath, and through-breath. He conquers both these worlds and the out-breath, down-breath, and through-breath, who, knowing thus, sings the Gāyatrī thrice without taking breath. Verily, he who knows the ten-day rite adapting through the Agniṣṭoma—it adapts for him: by the morning pressing, the first three-day period adapts; by the midday pressing, the second; by the third pressing, the third; by the Agniṣṭoma-sāman, the tenth day adapts. It adapts for him who knows thus.