Jaiminīya (Talavakāra) Brāhmaṇa 18.86

‘Run forward, O Pavamāna, the exhilarating Soma for Indra; / guided by men, you are led forth’— / this becomes a seven-verse hymn. / The breaths are seven. / Prospering through the breaths they proceed, standing firm in the breaths. / Then they say: ‘Since a seven-verse hymn is the characteristic mark of the seventh day, why then is it performed on the fifth day?’ / He should say: ‘The Śakvarī verses have seven metrical feet; the domestic cattle are seven; the meters increasing by four syllables are seven; the principal breaths are seven; the heavenly constellations are twenty-seven; this day is twenty-seven[-fold]. It is for obtaining all this, for attaining this.’ / The next hymn is a seven-verse hymn. / In regular order, prospering through the breaths, they proceed. / A four-verse hymn occurs: cattle are four-footed. / This day is cattle, [and this is] for the attainment of cattle. / There is a concluding verse, for the preservation of offspring and the securing of cattle. / The stoma is the twenty-seven-fold [stoma]. / These worlds are twenty-seven-fold. / In these very worlds they proceed, standing firm.

‘Bhūḥ’ is the mystical utterance.

It is this world: Agni is the deity, Gāyatrī the meter, the trivṛt the stoma, Rathantara the sāman, the Vasus the deities,

and the trees and herbs.