That thou art

Brahman is Satyam (Reality), Jnanam (Knowledge), Anantam (Infinity).
– Taittiriya Upanishad, 2.1.3

There is no second thing separate from It which It can see.
– Brhadaranyaka Upanishad, 4.3.23

Through the mind alone is It to be realised. There is no differentiation whatsoever in Brahman.
– Brhadaranyaka Upanishad, 4.4.19

In me, the limitless ocean, let the wave of the world rise or vanish of itself. I neither increase nor decrease thereby.
In me, the boundless ocean, is the imagination of the universe. I am quite tranquil and formless. In this alone do I abide.
– Astavakra Samhita, 7.2, 7.3