Śatapatha Brāhmaṇa ("of a hundred paths") 9.3.3.3

9.3.3.3

tadvai trayastriṃśāditi | anto vai trayastriṃśo 'yujāṃ stomānāmantata eva taddevāḥ svargaṃ lokamāyaṃstathaivaitadyajamāno 'ntata eva svargaṃ lokameti

Now this (set runs) up to the thirty-three-versed (hymn-form), for the Trayastrimsa is the last of the uneven Stomas: at the last the gods thus went up to heaven; and in like manner does the Sacrificer thereby at the last go up to heaven.