Śatapatha Brāhmaṇa ("of a hundred paths") 6.2.2.35

6.2.2.35

vapā paśupuroḍāśaḥ | tatṣaṣṭiḥ ṣaṣṭirmāsasyāhorātrāṇi tanmāsamāpnoti māsa āpta ṛtumāpnotyṛtuḥ saṃvatsaraṃ tatsaṃvatsaramagnimāpnoti ye ca saṃvatsare kāmā atha yadato 'nyadyadeva saṃvatsare 'nnaṃ tattat

The omentum and the animal cake, that makes sixty;--sixty are the days and nights of a month: thus he gains the month; the month gained gains the season; and the season (gains) the year: he thus gains the year, Agni, and the wishes which are contained in the year, and what other food than that there is in the year, all that (he gains).