Śatapatha Brāhmaṇa ("of a hundred paths") 4.4.5.3

4.4.5.3

māhirbhūrmā pṛdākuriti | asau vā ṛjīṣasya svagākāro yadenadapo 'bhyavaharantyathaiṣa evaitasya svagākāro rajjuriva hi sarpāḥ kūpā iva hi sarpāṇāmāyatanānyasti vai manuṣyāṇāṃ ca sarpāṇāṃ ca vibhrātṛvyamiva nettadataḥ sambhavaditi tasmādāha māhirbhūrmā pṛdākuriti

With (Vâg. S. VIII, 23), 'Be thou nor adder nor viper!' Now when they take the Soma-husks down to the water, that forsooth is the wishing of 'good-speed!' to it, and this now is the 'good-speed!' to him (the sacrificer); for snakes are like rope, and snakes' haunts are like wells (pits), and there is as it were a feud between men and snakes: 'Lest that should spring therefrom,' he thinks, and therefore he says, 'Be thou nor adder nor viper!'