Jaiminīya (Talavakāra) Brāhmaṇa 6.21

Equipped with out-breath and in-breath they thus proceed.
The stotriya is mind; the anurūpa is speech.
The stotriya is the sāman; the anurūpa is the verse.
The stotriya is the day; the anurūpa is the night.
The stotriya is this [earth]; the anurūpa is that [sky].
The stotriya is the self; the anurūpa is offspring.
Indeed, that form belongs to the stotriya and the anurūpa, because whatever excellent speech [the superior] speaks, the inferior repeats after him; because both the maker and the tool, being similar, are known [as such].
Because of the stotriya and the anurūpa, offspring are born conforming [to the father].
A [son] conforming to him is born in his offspring, who knows thus.
Regarding this they say: 'They are deprived of the breaths, who cut through the triplets of the introductory day.'
Here they perform five continuous triplets for the continuity of the breaths, so that there is no interruption.
All [the verses] contain the word 'bull'.
For this day is related to the Bṛhat.
[The bull] is the form of the Triṣṭubh, of the ruling class.
There is a concluding turn for the stability of offspring, for the presence of cattle.
There is the fifteenfold stoma — faculty and vital power, indeed, is the fifteenfold [stoma] — it is in faculty and vital power that they proceed establishing themselves.

"Agni, the messenger, we choose" —

thus [this] is the Ājya [śastra] dedicated to Agni.

Some ṛṣis saw with "pra-" [forth]; others with "ā-" [hither].

Now this [verse] stands neither with "pra-" nor with "ā-".