Jaiminīya (Talavakāra) Brāhmaṇa 1.181

These indeed are three [hymns]
having two deities: to Indra and Varuṇa, to Indra and Bṛhaspati, and to Indra and Viṣṇu.
With this much, they brought out these six wish-granting cows: cow and horse, goat and sheep, rice and barley.
These six wish-granting cows attend him who knows thus.
The sacrifice is just as extensive as the Agniṣṭoma.
Regarding this they say: 'Since the sacrifice is just as extensive as the Agniṣṭoma, when that has reached its end, towards what do they bring forward the ukthas?'
He should say: 'The verses of the Yajñāyajñīya are deficient by one syllable.
That is a hole in the sacrifice.
Thereby one places the sacrifice straight into it.'
They bring them forward onto [verses] addressed to Agni from [verses] addressed to Agni.
Just as one might put fires together upon fire, such is that.
He who, there being one fire, should disperse it manifoldly, there would be many [fires].
He who should bring them together, there being many, into one, there would be only one.
Just as one might put fires together upon fire, such is that.

Upon these [verses they sing] the Sākamaśva.

The gods, desirous of the heavenly world, performed ascetic heat.

They saw this sāman.

With it they praised.

Having become a horse, it carried them to the heavenly world.

Having gone to the heavenly world, they said: 'Together with the horse (sākam aśvena) indeed have we gone to the heavenly world.'

That is the Sākamaśva-nature of the Sākamaśva.

That is this heaven-winning sāman.

He reaches the heavenly world who knows thus.

One who has a rival should use the Pramaṃhiṣṭhīya.

Indra raised the thunderbolt against Vṛtra.

He was not able to strike him.