Shatapatha Brahmana 5.3.5.34

5.3.5.34

āvittau mitrāvaruṇau dhṛtavratāviti | prāṇodānau vai mitrāvaruṇau tadenam prāṇodānābhyāmāvedayati tāvasmai savamanumanyete tābhyāmanumataḥ sūyate

'Present are Mitra and Varuna, the upholders of the law;'--Mitra and Varuna are the out-breathing and in-breathing: he thus announces him to the out-breathing and in-breathing, and they approve of his consecration, and approved by them he is consecrated.