Śatapatha Brāhmaṇa ("of a hundred paths") 3.1.2.6

3.1.2.6

sa dakṣiṇamevāgre godānamabhyunatti | imā āpaḥ śamu me santu devīriti sa yadāhemā āpaḥ śamu me santu devīriti vajro vā āpo vajro hi vā āpastasmādyenaitā yanti nimnaṃ kurvanti yatropatiṣṭhante nirdahanti tattadetamevaitadvajraṃ śamayati tatho hainameṣa vajraḥ śānto na hinasti tasmādāhemā āpaḥ śamu me santu devīriti

His right whisker he moistens first, with the text, 'May these divine waters be propitious unto me! The reason why he says, 'May these divine waters be propitious unto me,' is this: the waters are a thunderbolt, for the waters are indeed a thunderbolt; hence wherever these waters flow they produce a hollow, and whatever they come near that they destroy (lit. burn up). Hereby, then, he appeases that same thunderbolt; and thus appeased, that thunderbolt does not injure him. This is why he says, 'May these divine waters be propitious unto me!'