Jaiminīya (Talavakāra) Brāhmaṇa 29.173

Prajāpati created this sacrifice, which is the twelve-day rite. He reached it entirely with the pṛṣṭhya six-day rite alone. He considered: "How now may I connect these four days?" Out of the Gāyatrī he fashioned the twenty-fourth day; out of the Triṣṭubh, the forty-fourth; out of the Jagatī, the forty-eighth; out of the Anuṣṭubh alone he fashioned the tenth day. Because he fashioned them out of all meters for all days, that is the essence of the chandomas. Concerning this, they say: "These stomas are attained, the meters are attained, the deities are attained, the seasons and soma cups are attained, when this pṛṣṭhya six-day rite is attained." As the Bahiṣpavamāna of the seventh day consists of twenty-four [verses]—the year has twenty-four half-months; the sacrifice is the year—it is the sacrifice itself that they take hold of at the beginning of the sacrifice. Moreover, the Gāyatrī has twenty-four syllables. It is the Gāyatrīs that extend again the attained sacrificial rite. For none other than the Gāyatrī is worthy to take up the attained sacrificial rite.

These [verses] are [used]:

"Pronouncing poetic wisdom like Uśanas..."

—thus [verses] containing the word "pra" on the introductory day.

This day is to be led forward.

"Pra" is the form of the Gāyatrī.

They go forth with the very form of the Gāyatrī.

"The god proclaiming the birth of the gods..."

—Soma is indeed the god proclaiming the birth of the gods.

They thereby engender Soma himself.

"Of great resolve, friend of the pure, purifying..."

—the gods call food "of pure resolve."

And Soma is the food of the gods.

It is that which they generate here.

"The boar approaches chanting with foot..."

Having indeed become a boar, Prajāpati stepped across from the sixth day to the seventh day.