REVEALED KNOWLEDGE

The Vedas are the revealed scriptures of the Indo-Aryans.  Vedas have two portions, the work portion and the knowledge portion.  The Upanishads is the knowledge portion.

The exact date of the Upanishads is unknown, possibly from 3000 BC to 800 BC.  The authorship is not certain; the authors who are named in it claim that they themselves were not the author, that the information was revealed to them.

The word “Upanishads” means to sit devotedly near.  A second meaning is secret knowledge.  A final meaning, provided by the philosopher-saint Shankara, is knowledge of Brahman leading to moksha, liberation. 
 
The three meanings can be combined as the supreme wisdom of Brahman that can be delivered by an illumined teacher as secret knowledge.