Śatapatha Brāhmaṇa ("of a hundred paths") 10.2.2.2

10.2.2.2

tasmādetadṛṣiṇābhyanūktam yajñena yajñamayajanta devā iti yajñena hi taṃ yajñamayajanta devāstāni dharmāṇi prathamānyāsanniti te hi dharmāḥ prathame'kriyanta te ha nākam mahimānaḥ sacanteti svargo vai loko nāko devā mahimānaste devāḥ svargaṃ lokaṃ sacanta ye taṃ yajñamayajannityetat

Wherefore it is with reference to this that the Rishi has said (Vâg. S. XXXI, 16, Rig-veda X, 90, 16), 'The gods offered up sacrifice by sacrifice,'--for by sacrifice they did offer up him (Pragâpati), the sacrifice;--'these were the first ordinances:'--for these laws were instituted first;--'these powers clung unto the firmament,'--the firmament is the world of heaven, and the powers are the gods: thus, 'Those gods who offered up that sacrifice shall cling to the world of heaven;'--