Śatapatha Brāhmaṇa ("of a hundred paths") 2.6.3.1

2.6.3.1

akṣayyaṃ ha vai sukṛtaṃ cāturmāsyayājino bhavati | saṃvatsaraṃ hi jayati tenāsyākṣayyam bhavati taṃ vai tredhā vibhajya yajati tredhā vibhajya prajayati sarvaṃ vai saṃvatsaraḥ sarvaṃ vā akṣayyameteno hāsyākṣayyaṃ sukṛtam bhavatyṛturu haivaitadbhūtvā devānapyetyakṣayyamu vaidevānāmeteno haivāsyākṣayyaṃ sukṛtam bhavatyetannu tadyasmāccāturmāsyairyajate

Verily, imperishable is the righteousness of him that offers the Seasonal sacrifices; for such a one gains the year, and hence there is no cessation for him. He gains it (the year) in three divisions, he conquers it in three divisions. The year means the whole, and the whole is imperishable (without end): hence his righteousness is indeed imperishable. Moreover, he thereby becomes a Season, and as such goes to the gods; but there is no perishableness in the gods, and hence there is imperishable righteousness for him. This, then, is why he offers the Seasonal sacrifices.