Jaiminīya (Talavakāra) Brāhmaṇa 1.27

1.27

Mounting the whirlwind as a chariot, he journeys from there toward co-existence with Āditya.
He offers for three days.
Twelve oblations are completed.
Twelve months are the year.
The year indeed is this all.
Whatever he eats here, whatever he drinks, to whomever he opens his mouth [to speak], all that becomes uneaten for him; he keeps the vow of fasting for as long as he lives.
This indeed is death, which is named Āditya the Setting One.
Having pacified him by means of those oblations, he conquers heaven among worlds, Āditya among gods.
He ascends to union, to co-existence with the god Āditya, who, knowing thus, offers the fire-offering.