This mass of writing, the VEDAS, is divided principally in to two parts, the Karma Kanda and the Jnana Kanda- the work portion and the knowledge portion, the ceremonial and the spiritual. The work portion consists of various sacrifices; most of them of late have been given up as not practicable under present circumstances, but others remain to the present day in some shape or other. The main ideas of the Karma Kanda, which consists of the duties of man, the duties of the student, of the householder, of the recluse, and the various duties of the different stations of life, are followed more or less down to the present day. But the spiritual portion of our religion is in the second part, the Jnana Kanda, the Vedanta, the end of the Vedas, the Gist, the Goal of the Vedas.
The essence of the knowledge of the Vedas was called by the name of Vedanta, which comprises the UPANISHADS; and all the sects of INDIA- Dualists, Qualified-Monists, Monists, or the Shaivites, Vaishnavites Shaktas, Sauras, Ganapatyas, each one that dares to come within the fold of Hinduism- must acknowledge the Upanishads of the Vedas. They can have their own interpretations and can interpret them in their own way, but they must obey the authority. That is why we want to use the word Vedantist instead of Hindu. All the Philosophers of India who are orthodox have to acknowledge the authority of the Vedanta; and all our present day religions, however crude some of them may appear to be, however inexplicable some of their purposes may seem, one who understands them and studies them can trace them back to the ideas of the Upanishads. So deeply have these Upanishads sunk into our race that those of you who study the symbology of the crudest religion of the Hindus will be astonished to find sometimes figurative expressions of the Upanishads- the Upanishads become symbolized after a time into figures and so forth. Great spiritual and philosophical ideas in the Upanishads are today with us, converted in to household worship in the form of symbols. Thus the various symbols now used by us, all come from the Vedanta, because in the Vedanta they are used as figures, and these ideas spread among the nation and permeated it throughout until they became part of their everyday life as symbols.
From the Work Essentials Of Hinduism By Swami Vivekananda.