In Hinduism, upadesha is imparting knowledge by a teacher to this disciple. Adi Shankaracharya recorded dialogues between the teacher and the student in a book titled Upadeshahasri or A Thousand Teachings. The work devotees itself to the question of duality or plurality between human beings and God. It concludes with an emphatic ‘Thou art that (tat tvam asi). Accordingly, selves could not be plural or different, as they would limit each other and destroy each other.
Shankaracharya argues that the creator and creation represent tattva (the principle of Brahman), which alone is the reality, and the rest exists in maya (the non-real perceived as relative, plural and differentiated). Like a dream, maya exists and yet it does not exist. The knowledge of this all-pervading principle or changeless Reality called God needs no evidence. The proof is regarded as transitory knowledge, because proof itself is an object on intelligence. No object in the world is real. In fact, according to Sahasropadesi, there exists now knowledge or ignorance in anyone. It is only homogenous consciousness that exits. This is compared with the state of the sun, which is neither day nor night but only light. Pain, pleasure, etc., are all unreal and nothing but modifications of the intellect and not knowledge. According to Shankaracharya, to experience the eternal truth, eternal knowledge is required. Knowledge is pure consciousness, omnipresent in the hearts of all beings, while ignorance is superimposition of the ego on the self.
Renunciation of worldly life is the best means of liberating the self from the ego. On the authority of Shrutis (Hindu testaments), Adi Shankaracharya regards renunciation of action superior to the performance of actions. Actions, according to Shrutis, result only in production, acquisition, transformation, and purification of things which are of no consequence or achieving peace. Hence all such actions must be renounced in search of truth. This need not mean passivity or ending life. Routine duties are to be performed. The stress here is on knowledge-motivated deeds (karmas). Right knowledge automatically leads to right deeds.
Right knowledge, according to the Advaita philosophy, is soham (I am Him – I am Brahman). The Brahman has no form, color, or the like. It is not capable of being rejected, accepted, and produced or amended. It is the doer of everything. Nevertheless, being everything, it is not created. It simply exists. Just as drops in the ocean are not separate elements but the ocean themselves, individual elements are the whole entity itself. This is like zero being infinity and infinity being zero. By loving or respecting other elements, human beings respect themselves or God in them. The truth lies beyond maya, and when it is discovered, peace prevails: this is Shankaracharya’s upadesha.