Tat Tvam Asi ("You're it.")
One of the "great utterances" (mahavakyas)
conveying the ultimate truth in Hindu philosophical tradition.
The fact in question is the identity of atman (individual
Self) and Brahman (Supreme Reality); this identity is at the center of the
Upanishads, a collection of theoretical literature.
This particular verse appears many times in the Chandogya
Upanishad's sixth book, when the youngster Shvetaketu is being schooled by his
father.
The boy's father conveys his lesson about the identical
natures of the atman and Brahman via a succession of parallels, each
culminating with this final remark, which encapsulates the wisdom of the whole.
This and three other mahavakyas—as statements that encapsulate
essential truth—were seized as distinguishing symbols by the four divisions of
the Dashanami Sanyasi ascetics, in addition to their textual significance.
Each division had its own mahavakya, just as each division
had its own Veda, principal holy center, and archetypal ascetic trait.
Tat tvam asi is a mahavakya linked with the Dashanami
Sanyasis' Kitawara division.