Brihadaranyaka Upanishad 6.4.28

6.4.28

athāsya mātaramabhimantrayate | ilāsi maitrāvaruṇī vīre vīramajījanat | sā tvaṃ vīravatī bhava yāsmānvīravato'karaditi taṃ vā etamāhuratipitā batābhūratipitāmaho batābhūḥ paramāṃ bata kāṣṭhāṃ prāpacchriyā yaśasā brahmavarcasena ya evaṃvido brāhmaṇasya putro jāyata iti

Then he addresses the mother: 'You are the adorable Arundhatī, the wife of Vasiṣṭha; you have brought forth a male child with the help of me, who am a man. Be the mother of many sons, for you have given us a son.' Of him who is born as the child of a Brāhmaṇa with this particular knowledge, they say, 'You have exceeded your father, and you have exceeded your grandfather. You have reached the extreme limit of attainment through your splendour, fame and Brāhmanical power.'

6.4.28.p1

iti ṣaṣṭhādhyāye caturthaṃ brāhmaṇam