Jaiminīya (Talavakāra) Brāhmaṇa 12.51

Now the Pāṣṭhauha [sāman].
Pāṣṭhauhi Āṅgirasa, desiring the heavenly world, performed austerities.
He saw this sāman.
He praised with it.
Then indeed he attained the heavenly world.
This is a heaven-procuring sāman.
He who knows thus attains the heavenly world.
Because Pāṣṭhauhi Āṅgirasa saw it, therefore it is called the Pāṣṭhauha.
And indeed these two sāmans are the invocation and the response: "ho ye ho vā hā ho"
—by this the Aṅgirases called;
"hā o vā o vā"—by this they responded.
These two sāmans are indeed the invocation and the response, leading to heaven, for the attainment of the heavenly world.
"Press, pour around..."
—they contain the word "pari" ("around"), the form of the end.
For this day is the end.

On them [is sung] the sāman of Speech.

For atonement, the gods sit at sacrificial session.