All this is Brahman. Let a man meditate on that (visible world) as beginning, ending, and breathing in it (the Brahman)…
…He is my self within the heart, smaller than a corn of rice, smaller than a corn of barley, smaller than a mustard seed, smaller than a canary seed or the kernel of a canary seed. He is also myself within the heart, greater than the earth, greater than the sky, greater than heaven, greater than all these worlds.
– Khândogya-Upanishad 3.14 1, 3