Shatapatha Brahmana 5.2.5.16

5.2.5.16

atha yadvāruṇo yavamayaścarurbhavati | tatsarvasmādevaitadvaruṇapāśātsarvasmādvaruṇyātprajāḥ pramuñcati tā asyānamīvā akilviṣāḥ prajāḥ prajāyante 'namīvā akilviṣāḥ prajā abhi sūyā iti

And as to why there is a barley pap for Varuna; he thereby frees the creatures from every snare of Varuna, from all that comes from Varuna; and those creatures of his are produced sound and faultless: 'May I be consecrated for sound and faultless creatures (or subjects)!' he thinks.