Upanishads, the Source of Indian Spiritual Manifestations

Upanishads"1, also called "Vedanta"2 or “end of Veda”, refers to the end of "Vedas"3. According to the classification of Hindu sacred works, Upanishads are supplementary writings attached to "Aranyaka"4. Based on Hindu traditions, the wise people and receivers of the Divine Commandments were the creators of Upanishads. These people, who were called "Caviya Satiya Sarvata"5, used to live deep in untouched and dark jungles of India where they meditated and studied their own self. They expressed the spiritual experiences inspired to them (by the Divine Source) and flowed within their souls, in the form of Wahdat al-Wujud (Unity of Existence), decorated them with the dressing of mysterious words, and formed them as compressed synthetic ideas. The era of jungle-life was started with the theses of "Aranyaka" and ended with Upanishads, a period which can metaphorically be called the education period in the depth of jungle.
According to Max Muller's theory, Upanishads are the oral teachings of masters (morshids) to their close followers. It must be noted that most of the prominent theoretical schools in India and even in Buddhism have originated from Upanishads.
With regard to the main subject in "Upanishads", the present paper tries to establish the specific spirituality, self-purification and the unique truth of the ancient India.