Śatapatha Brāhmaṇa ("of a hundred paths") 7.4.2.27

7.4.2.27

prajāpatiṣṭvā sādayatviti | prajāpatirhyetām prathamāṃ citimapaśyatpṛṣṭhe pṛthivyā jyotiṣmatīmiti pṛṣṭhe hyayam pṛthivyai jyotiṣmānagniḥ

[He lays it down, with Vâg. S. XIII, 24] 'May Pragâpati settle thee'--for Pragâpati saw this first layer;--'on the back of the earth, thee the brilliant one!' for on the back of the earth this brilliant Agni indeed is.