Shatapatha Brahmana 11.2.7.15

11.2.7.15

kṣatramupāṃśuyājaḥ sa yo ha vai kṣatramupāṃśuyāja iti vedāva ha kṣatraṃ runddhe'tho yatkiṃ ca kṣatreṇa jayyaṃ sarvaṃ haiva tajjayati tadyadupāṃśuyājaṃ kurvantyeke naike tasmāduccaiścopāṃśu ca kṣatrāyācakṣate

The low-voiced offering is the Kshatra (nobility); and, verily, whosoever knows the low-voiced offering to be the nobility secures for himself the nobility; and whatever is to be gained by the nobility all that he now gains. And inasmuch as some perform the low-voiced offering, and others do not. therefore people speak (give information) to the noble both in a loud voice and in a low voice.