स य एषोऽणिमैतदात्म्यमिदँ सर्वं तत्सत्यँ स आत्मा तत्त्वमसि श्वेतकेतो इति भूय एव मा भगवान्विज्ञापयत्विति तथा सोम्येति होवाच ॥ ३ ॥
In plain words
That subtle essence is the Self of all this universe. That is the Truth; that is the Self. And you are That, O Shvetaketu. 'Instruct me further, revered sir,' the son requested. 'So be it, my dear,' the father replied.
Close to the Sanskrit
That which is this subtlety, this entire universe has that as its self. That is the Truth, that is the Self. Thou art that, O Shvetaketu. 'Teach me further still, revered sir,' [he said]. 'So be it, my dear,' he said.