Shatapatha Brahmana 4.5.1.3

4.5.1.3

sa vai pathyāmevāgre svastiṃ yajati | taddevā aprajñāyamāne vācaiva pratyapadyanta vācā hi mugdham prajñāyate 'thātra prajñāte yathāpūrvaṃ karoti

To Pathyâ Svasti he offers first (at the opening sacrifice): then the gods, through speech, saw their way in what was unknown to them, for by speech the confused becomes known. But now that it is known, he performs in the proper order.