Shatapatha Brahmana 6.6.3.15

6.6.3.15

atha kṣatriyasya | udeṣām bāhū atiramudvarco atho balam kṣiṇomi brahmaṇāmitrānunnayāmi svāṃ ahamiti yathaiva kṣiṇuyādamitrānunnayetsvānevametadāhobhetvevaite ādadhyādayaṃ vā agnirbrahma ca kṣatraṃ cemamevaitadagnimetābhyāmubhābhyāṃ saminddhe brahmaṇā ca kṣatreṇa ca

And in the case of a nobleman, with (Vâg. S. XI, 82),'I have raised their arms, their lustre and strength: by the spiritual power I destroy the enemies, and elevate mine own (relatives)!' this he says with the view that he may destroy his enemies, and elevate his own relatives. Let him put on both these (kindling-sticks); for both the Brahman and the Kshatra are this Agni; and it is this Agni he thus kindles by those two, by the Brahman and the Kshatra.