The Four Principles Mahavakyas
“Consciousness is Brahman.”
prajñānam brahma – (Aitareya Upanishad 3.1.3)
(‘Consciousness is Ultimate Reality’)
“I am Brahman.”
aham brahmāsmi – (Brihadaranyaka Upanishad 1.4.10)
“That thou art.” – (“You are Brahman.”)
Tat Tvam Asi – (Chandogya Upanishad 6.8.7)
“This Self is Brahman.”
ayam ātmā brahma – (Mandukya Upanishad 2.)
(‘This Self’ = Atman, the Soul = You.)
Other Mahavakyas
Brahman alone is real; the world is the appearance.
brahma satyam jagan mithyā – (Shankara, Vivekachudamani)
Brahman is one, without a second.
ekam evadvitiyam brahma – (Chāndogya Upaniṣad)
He am I.
So ‘ham – (Isha Upanishad)
All this is Brahman.
Sarvam khalvidam brahma. – (Chandogya Upanishad 3.14.1)