Śatapatha Brāhmaṇa ("of a hundred paths") 14.1.3.33

14.1.3.33

sa yatraitāṃ hotānvāha apnasvatīmaśvinā vācamasme iti tadadhvaryurupottiṣṭhannāha rucito gharma iti sa yadi rucitaḥ syācreyānyajamāno bhaviṣyatīti vidyādatha yadyarucitaḥ pāpīyānbhaviṣyatīti vidyādatha yadi naiva rucito nārucito naiva śreyanna pāpīyānbhaviṣyatīti vidyādyathā nveva rucitaḥ syāttathā dhavitavyaḥ

And when the Hotri recites this (verse, Rig-v. I, 112, 24), 'Successful, O Asvins, make ye our voice,' the Adhvaryu steps up, and says, 'The Gharma is aglow.' If it be aglow, he may know that the Sacrificer will become more prosperous; and if it be not aglow, he may know that he will become poorer; and if it be neither aglow nor the reverse, he may know that he (the Sacrificer) will become neither more prosperous nor poorer: but indeed (the pot) should be fanned so (long) as to be aglow.