Shatapatha Brahmana 6.3.3.1

6.3.3.1

pradīptā ete 'gnayo bhavanti | atha mṛdamacayantīme vai lokā ete 'gnayaste yadā pradīptā athaita ime lokāḥ puro vā etadebhyo lokebhyo >gre devāḥ karmānvaicaṃstadyadetānagnīnatītya mṛdamāharati tadenam puraibhyo lokebhyo 'nvicati

Those fires have been kindled (afresh); and they (the priests and sacrificer) betake themselves to the lump of clay;--those fires doubtless are these worlds: when they are kindled, then they are these worlds. For formerly the gods were seeking this sacred rite outside of these worlds; and when he fetches the lump of clay after passing by those fires, he is seeking him (Agni) outside of these worlds.