Śatapatha Brāhmaṇa ("of a hundred paths") 13.4.1.1

13.4.1.1

prajāpatirakāmayata sarvānkāmānāpnuyāṃ sarvā vyaṣṭīrvyaśnuvīyeti sa etamaśvamedhaṃ trirātraṃ yajñakratumapaśyattamāharattenāyajata teneṣṭvā sarvānkāmānāpnotsarvā vyaṣṭīrvyāśnuta sarvānha vai kāmānāpnoti sarvā vyaṣṭīrvyaśnute yo'śvamedhena yajate

Pragâpati desired, 'Would that I obtained all my desires! would that I attained all attainments!' He beheld this three days’ Soma-sacrifice, the Asvamedha, and took possession of it, and sacrificed with it: by sacrificing therewith he obtained all his desires, and attained all attainments; and, verily, whosoever performs the Asvamedha sacrifice obtains all his desires, and attains all attainments.