The body is the temple of God; He is resident in the heart; buddhi (intelligence) is the lamp lit in that altar; now, every gust of wind that blows through the windows of the senses affects the flame of the lamp and dulls its light, threatening even to put it out. So, close the windows; do not keep them open for dire attraction from objects. Keep buddhi sharp, so that it may cut the mind like a diamond and convert it into a blaze of light, instead of being a dull pebble. Discrimination (nityanitya vastu viveka or distinguishing between the eternal and temporary) is an important instrument of spiritual progress. The reasoning faculty must be employed to distinguish between the limited and the unlimited, the temporary and the Eternal. That is its legitimate use. Shankaracharya names his work on the principles of Advaita as “Viveka Chudamani”, for he wanted to emphasise the value of viveka for the realisation of the evanescence of life and the Oneness of the Universe. – Divine Discourse, Oct 02, 1965.