Upanishads

The Upanishads are a body of Sanskrit texts composed from roughly the eighth century BCE onward, forming the concluding portion of the Vedas. They are dialogues and speculations concerned with the relation between the self (atman) and ultimate reality (brahman).

Their quotational importance rests on the mahavakyas, the 'great sayings' — extremely short formulas such as tat tvam asi ('that thou art') and aham brahmasmi ('I am brahman') — which later Vedanta traditions treated as condensations of the entire teaching.

Because the formulas are so short, translation choices carry enormous weight, and rival philosophical schools read the same four words in incompatible ways. Citing an Upanishad therefore means naming both the text (Chandogya, Brihadaranyaka, Katha, Isha) and the chapter and verse.

Common mistake: quoting a mahavakya as a standalone motivational line. In context each is the conclusion of a long argument, and the dialogue supplies the sense in which the identity is asserted.