Jaiminīya (Talavakāra) Brāhmaṇa 1.113

1.113

devānvai yajñasyāhutirnāgacchat
sa prajāpatirāiksata kathaṃ nu devānyajñasyāhutirgacchediti
sa ete dve akṣare gāyatryā udakhidat
sa eva dvyakṣaro vaṣaṭkāro'bhavattato vai devānyajñasyāhutiragacchat
annaṃ vai vaṣaṭkāraḥ
attyannaṃ ya evaṃ veda
indro vṛtrāya vajramudayacchat
tasyaite akṣare cakrāvāstām
vajro vā eṣaḥ
ya ete nispṛśedvajraṃ nispṛśet
yo vai dugdhāddugdhamupaiti na sa āpyāyate
atha yo'dugdhāddugdhamupaiti sa āpyāyate
dugdhādvā eṣa dugdhamupaiti ya ete akṣare upaiti
tasmādete akṣare nopetye
yasya vai sarvā gāyatrī gīyate sarvamasya gṛhe adhigamyate
yasyo nāgīyata īśvaro rūkṣo bhavitoḥ
anyataradakṣaramavagṛhya vācaṃ caturviṃśīmupeyāt
nāsyonā gāyatrī gīyate ni ca spṛśati na ca

The oblation of the sacrifice did not reach the gods. Prajāpati considered: "How, indeed, may the oblation of the sacrifice reach the gods?" He pulled out these two syllables from the Gāyatrī. That became the two-syllable vaṣaṭ-call; thereupon the oblation of the sacrifice reached the gods. Food, indeed, is the vaṣaṭ-call. He who knows this eats food. Indra raised his thunderbolt against Vṛtra; these two syllables were its two wheels. That is indeed a thunderbolt. Whoever touches these touches a thunderbolt. He who approaches milk from what has already been milked is not nourished; but he who approaches milk from what has not been milked is nourished. He who approaches these two syllables approaches milk from what has already been milked. Therefore, these two syllables should not be approached. He for whom the entire Gāyatrī is sung, everything is obtained in his house. And he for whom it is sung deficient, he is likely to become withered. Having held back one or the other syllable, he should approach speech as twenty-fourfold. His Gāyatrī is neither sung deficient, nor does he touch [the thunderbolt].