Śatapatha Brāhmaṇa ("of a hundred paths") 9.2.3.34

9.2.3.34

athainaṃ nidadhāti | suparṇo 'si garutmānityetadvā enamado vikṛtya suparṇaṃ garutmantaṃ vikaroti taṃ suparṇaṃ garutmantaṃ cinoti taṃ suparṇaṃ garutmantaṃ kṛtvāntato nidadhāti pṛṣṭhe pṛthivyāḥ sīda bhāsāntarikṣamāpṛṇa jyotiṣā divamuttabhāna tejasā diśa uddūṃhetyevaṃ hyeṣa etatsarvaṃ karoti

He then lays it (the firebrand) down, with (Vâg. S. XVII, 72, 73), 'A well-winged bird thou art,'--for on that former occasion he, by means of the fashioning-formula, fashions him into a well-winged bird; that well-winged bird he builds up, and having fashioned that well-winged bird, he finally sets him down;--'seat thee on the back of the earth, fill the air with thy shine, prop the sky with thy light, and uphold the quarters by thy lustre!'--for that one (Agni) indeed does all this.