Śatapatha Brāhmaṇa ("of a hundred paths") 1.6.4.13

1.6.4.13

tadvā etadeva vārtraghnam | yatpaurṇamāsamathaiṣa eva vṛtro yaccandramāḥ sa yatraiṣa etāṃ rātriṃ na purastānna paścāddadṛśe tadenametena sarvaṃ hanti nāsya kiṃ cana pariśinaṣṭi sarvaṃ ha vai pāpmānaṃ hanti na pāpmanaḥ kiṃ cana pariśinaṣṭi ya evametadveda

An offering in honour of the Vritra-slayer, then, is the full-moon sacrifice. Vritra, assuredly, is no other than the moon; and when during that night (of new moon) he is not seen either in the east or in the west, then he (Indra) completely destroys him by means of that (new-moon sacrifice), and leaves nothing remaining of him. And, verily, he who knows this, overcomes all evil and leaves nothing remaining of evil.