Jaiminīya (Talavakāra) Brāhmaṇa 2-8.303

With this very [rite], indeed, Janaka Vaideha desired to sacrifice.
When the Brahmins of the Kuru-Pañcālas said to him, 'Let us sacrifice for you with this sacrifice; let us sacrifice for you with this sacrifice,'
he said: 'No.
There was no Brahmin among you more devoted to brahman than he who arranged this sacrificial rite for me.
Sacrifice for me with this very one.'
'So be it,' [they said].
With that very [rite] they sacrificed for him.
It is that very Pṛṣṭhya Ṣaḍaha, [along with] the twenty-five-fold Mahāvrata.
From that they enter directly upon the night.
Prosperity, indeed, the highest summit, is the pṛṣṭhas.
It is prosperity, the highest summit, the pṛṣṭhas, that he ascends to.
Food, indeed, is the Mahāvrata, for the securing of proper food.
Regarding this they say: 'The Mahāvrata is not to be undertaken before a year.'
Now, in that it is the Pṛṣṭhya Ṣaḍaha: the seasons, indeed, are the pṛṣṭhas.
The year is the seasons.
The year ripens all proper food; it is food conquered by the year that they attain.
The twenty-five-fold is the Mahāvrata; food, indeed, is the twenty-five-fold, for the securing of proper food.

Regarding this they say: 'This day occupies the place of a day-and-night; this day is an Agniṣṭoma.'

And regarding this they also say: 'This Agniṣṭoma, indeed, is the year.'

The year is Prajāpati.

Belonging to Prajāpati is the Mahāvrata; the chants of the Agniṣṭoma-sāman should be twenty-five-fold.

'Then they should descend to the night with twenty-one-fold Ukthyas,' [they say].

In this way these two sacrificial rites are distinguished.

Now, regarding that rite of which the stomas of the Pṛṣṭhya Ṣaḍaha [are used], with the Mahāvrata on the fifth day,

and the Viśvajit Sarvapṛṣṭha Atirātra—with this Kratu Kārīrādi sacrificed, desirous of prosperity, desirous of proper food.