Śatapatha Brāhmaṇa ("of a hundred paths") 6.2.1.32

6.2.1.32

sa etā aṣaśyat | ūrdhvā asya samidho bhavantītyūrdhvā hyetasya samiddhasya samidho bhavantyūrdhvā śukrā śocīṃṣyagnerityūrdhvāni hyetasya śukrāṇi śocīṃṣyarcīṃṣi bhavanti dyumattameti vīryavattametyetatsupratīkasyeti sarvato vā agniḥ supratīkaḥ sūnoriti yadenaṃ janayati tenāsyaiṣa sūnuḥ

He saw these (verses):--'Upright are his kindling-sticks,' for upright indeed are the kindling-sticks of him when kindled;--'upwards tending the bright flashes of Agni,' for tending upwards are his bright flashes, his flames;--'they, the most brilliant,' that is 'the most powerful;'--'of the fair-looking son,' for fair-looking indeed Agni is on all sides; and inasmuch as he (the Sacrificer) produces him thereby he (Agni) is his son.