Shatapatha Brahmana 13.2.11.1

13.2.11.1

prajāpatirakāmayata mahānbhūyāntsyāmiti sa etāvaśvamedhe mahimānau grahāvapaśyattāvajuhottato vai sa mahānbhūyānabhavatsa yaḥ kāmayeta mahānbhūyāntsyāmiti sa etāvaśvamedhe mahimānau grahau juhuyānmahānhaiva bhūyānbhavati

Pragâpati desired, 'Would that I were great, and more numerous!' He perceived those two Mahiman (greatness) cups of Soma at the Asvamedha; he offered them; and thereby, indeed, became great and more numerous: hence whosoever should desire to become great, and more numerous, let him offer up those two Mahiman cups of Soma at the Asvamedha; and he indeed becomes great and more numerous.