Shatapatha Brahmana 9.3.4.5

9.3.4.5

yadvevaitadvājaprasavīyaṃ juhoti | etā ha devatāḥ sutā etena savena yenaitatsoṣyamāṇo bhavati tā evaitatprīṇāti tā asmā iṣṭāḥ prītā etaṃ savamanumanyante tābhiranumataḥ sūyate yasmai vai rājāno rājyamanumanyante sa rājā bhavati na sa yasmai na tadyadagnau juhoti tadagnimabhiṣiñcatyatha yadetābhyo devatābhyo juhoti tadu tāndevānprīṇāti ya etasya savasyeśate

And, again, as to why he performs the Vâgaprasavîya;--he thereby gratifies those same deities who have been consecrated by this very rite of consecration by which he is now about to be consecrated, and, thus gratified by offering, they grant him permission (to perform) this rite of consecration, and, permitted by them, he becomes consecrated; for only he becomes king whom the (other) kings allow to assume the royal dignity, but not he whom they do not (allow to do so). Thus when he offers in the fire he consecrates Agni, and when he offers to these deities, he gratifies those gods who rule over this consecration ceremony.