To light a lamp, you need four things - a container, oil, a wick and a match box. If any one of these is missing, you cannot light the lamp. This lamp can, however, remove only the outside darkness. How is the darkness in the heart to be removed? It can be dispelled only by the Light of Wisdom (Jnana Jyothi). How is this Light of Wisdom, this spiritual light, to be lit? This also needs four elements - detachment (Vairagya) is the container, devotion (Bhakti) is the oil, one-pointed concentration (Ekagrata) is the wick and knowledge of the Supreme Truth (Jnana) is the match stick. Without these four, the light of spiritual wisdom cannot shine. Of these, primary requisite is the spirit of vairagya (renunciation). Without detachment, all knowledge of scriptures is of no avail. What is this detachment? It is absence of attachment to the body. Give up the ego-feeling, which makes one think of the "I" all the time. (Divine Discourse, Nov 9, 1988.)