Those who received revelation have given us sacred books such as the Bible, the Qur'an, the Bhagavad Gita; hundreds and thousands of years have passed and their sacred teachings have remained alive even now. But at the same time we must know that what they have given in the form of preaching, in the form of teachings, is the interpretation of the living wisdom which cannot be fully expressed in words. One can only know that living knowledge when one has experienced it oneself by the opening of the heart. It is then that the purpose of life is fulfilled.