Uddalaka and Svetaketu
Chandogya Upanishad 6.8.7
Source: verified public-domain translation.
Original text
स य एषोऽणिमैतदात्म्यमिदं सर्वं तत्सत्यं स आत्मा तत्त्वमसि श्वेतकेतो इति
Transliteration
sa ya eṣo ’ṇimaitadātmyam idaṃ sarvaṃ tat satyaṃ sa ātmā tattvamasi śvetaketo iti
Translation
“Now that which is that subtle essence, in it all that exists has its self. It is the True. It is the Self, and thou, O Śvetaketu, art it.”
Translation · F. Max Müller
Context
One of nine repetitions of tat tvam asi in Chandogya 6, taught by Uddalaka Aruni to his son. Advaita takes it as a mahavakya of identity. Other Vedantic schools read the grammar and the metaphysics differently. Both are traditional.