Jaiminīya (Talavakāra) Brāhmaṇa 31.184

31.184

abhitapati bhrātṛvyaṃ śreyānbhūtvā ya evaṃ veda
tadāgneyaṃ sāmāgneye'hankriyate
āgneyametadaharyadgāyatram
agnirhi gāyatrī
tadyadatra rauravaṃ kriyate'hareva tadrūpeṇa samardhayanti
tenaibhyassamṛddhena svāyāṃ janatāyāmṛddhukaṃ bhavati
tadaiḷe bhavati paśavo vā iḷā
paśavaśchandomāḥ paśūnāmevāvaruddhyai
atha rathantaram
jāmi dvādaśāhasyāstītyāhuḥ
bārhataṃ ṣaṣṭhamaharbārhataṃ saptamam
pavamāne rathantaraṃ prohantyajāmitāyai
nānyato'pasakto vivadho hriyata ityāhuḥ
tadyadubhe bṛhadrathantare bhavatassa vivadhatāyā eva
yo vai mūlādagraṃ saṃcikramiṣati na sa śaknoty | atha yo'grādagraṃ saṃkrāmati
sa śaknoti
agrādvā ete'graṃ saṃkrāmanti ye bṛhato bṛhadupayanti
tasmādbārhataṃ ṣaṣṭhamaharbhavati | bārhataṃ saptamam

Becoming superior, he scorches his rival, who knows thus.
That sāman belonging to Agni is performed on a day belonging to Agni.
This day, which is the Gāyatra, belongs to Agni,
for Agni is the Gāyatrī.
Therefore, that the Raurava is performed here, thereby they make the day prosper in its own form.
By that prospering [day], it becomes prosperous for them among their own people.
It is set on an Iḷā-ending [verse], for cattle are iḷā;
the Chandomas are cattle, for the securing of cattle.
Now, the Rathantara.
They say: "There is a monotony in the twelve-day rite;
the sixth day is connected with the Bṛhat, the seventh day is connected with the Bṛhat."
In the Pavamāna [lauda], they introduce the Rathantara to avoid monotony.
They say: "A carrying-pole (vivadha) fastened on only one side is not carried [well]."
Therefore, that both the Bṛhat and the Rathantara are present is for the sake of being a carrying-pole.
Whoever wishes to step from the root to the top is not able; but whoever steps from top to top is able.
Those who go from the Bṛhat to the Bṛhat step from top to top.
Therefore, the sixth day is connected with the Bṛhat; the seventh day is connected with the Bṛhat.