Śatapatha Brāhmaṇa ("of a hundred paths") 4.3.3.4

4.3.3.4

tānvā etān | pañca grahāngṛhṇātyeṣa vai vajro yanmādhyandinaḥ pavamānastasmātpañcadaśaḥ pañcasāmā bhavati pañcadaśo hi vajraḥ sa etaiḥ pañcabhirgrahaiḥ pañca vā imā aṅgulayo 'ṅgulibhirvai praharati

These, then, are five grahas he draws; for that midday Pavamâna chant is a thunderbolt: hence it is a fifteenfold five-hymned chant, for the thunderbolt is fifteenfold. He is so by means of these five grahas (cups of Soma): for five are these fingers, and with the fingers he hurls (the thunderbolt).