Śatapatha Brāhmaṇa ("of a hundred paths") 5.1.4.3

5.1.4.3

atha rathamupāvaharati | indrasya vajro 'sīti vajro vai ratha indro vai yajamānastasmādāhendrasya vajro 'sīti vājasā iti vājasā hi rathastvayāyaṃ vājaṃ sedityannaṃ vai vājastvayāyamannamujjayatvityevaitadāha

He takes down the chariot, with (Vâg. S. IX, 5), 'Thou art Indra's thunderbolt;' for the chariot is indeed a thunderbolt, and the sacrificer is Indra: therefore he says, 'Thou art Indra's thunderbolt;'--'a winner of wealth,' for the chariot is indeed a winner of wealth;--'May this one win wealth by thee!'--wealth means food: 'may this one gain food by thee,' is what he thereby says.