Śatapatha Brāhmaṇa ("of a hundred paths") 5.3.4.27

5.3.4.27

tāḥ sārdhamaudumbare pātre samavanayati | madhumatīrmadhumatībhiḥ pṛcyantāmiti rasavatī rasavatībhiḥ pṛcyantāmityevaitadāha mahi kṣatraṃ kṣatriyāya vanvānā iti tatparo 'kṣaṃ yajamānāyāśiṣamāśāste yadāha mahi kṣatraṃ kṣatriyāya vanvānā iti

He pours them together into an udumbara vessel with, 'Let the honey-sweet mix with the honey-sweet!'--'Let those full of essence mix with those full of essence!' he thereby says;--'Winning great power (kshatra) for the Kshatriya!' in saying this he prays in a covert way for power to the Sacrificer.