Shatapatha Brahmana 10.4.5.1

10.4.5.1

athādeśā upaniṣadām vāyuragniriti ha śākāyanina upāsata ādityo'gnirityu haika āhuratha ha smāha śraumatyo vā hāliṅgavo vā vāyurevāgnistasmādyadaivādhvaryuruttamaṃ karma karotyathaitamevāpyetīti

Now the doctrines of mystic imports. The Sâkâyanins hold that 'Agni is Vâyu (the wind);' but some say that 'Agni is Âditya (the sun).' And either Sraumatya, or Hâliṅgava, said, 'Agni is no other than Vâyu: wherefore the Adhvaryu, when he performs the last work, passes into that (wind).'