गवन्वेदेति सोऽब्रवीत्पतञ्चलं काप्यंयाज्ञिकांश्च यो वै तत्काप्य सूत्रंविद्यात्तं चान्तर्यामिणमिति स ब्रह्मवि-त्स लोकवित्स देववित्स वेदवित्सभूतवित्स आत्मवित्स सर्वविदिति ते-भ्योऽब्रवीत्तदहं वेद तच्चेत्त्वं याज्ञवल्क्यसूत्रमविद्वांस्तं चान्तर्यामिणं ब्रह्मगवी-रुदजसे मूर्धा ते विपतिष्यतीति वेद वाअहं गौतम तत्सूत्रं तं चान्तर्यामिणमि-ति यो वा इदं कश्चिद्ब्रूयाद्वेद वेदेतियथा वेत्थ तथा ब्रूहीति ॥ १ ॥
In plain words
'...I know that, revered sir,' he said. The Gandharva told Patancala Kapya and the ritual priests: 'Whoever truly knows that thread, and knows the inner controller within it, knows brahman, knows the worlds, knows the gods, knows the Vedas, knows every being, knows the self, knows everything there is.' He said this to them. 'I know it,' said Uddalaka. 'And if you, Yajnavalkya, don't know that thread and that inner controller, and still you drive off the cows set aside for those who do know brahman -- your head will fall off.' Yajnavalkya answered, 'I do know it, Gautama -- both the thread and the inner controller.' Uddalaka said, 'Anyone can say I know, I know. Tell it the way you actually know it.'
Close to the Sanskrit
'...I know, revered sir,' he said. He said to Patancala Kapya and the ritual priests: 'Whoever indeed, O Kapya, would know that thread and would know that inner controller -- he is a knower of brahman, he is a knower of the worlds, he is a knower of the gods, he is a knower of the Vedas, he is a knower of beings, he is a knower of the self, he is a knower of all.' He said this to them. 'I know that. If you, Yajnavalkya, being ignorant of that thread and that inner controller, drive off the cows of the knowers of brahman, then your head will fall off.' 'I do indeed know, Gautama, that thread and that inner controller.' 'Anyone at all could say this -- I know, I know. Tell it as you actually know it.'