Sri Krishna has explained in the Gita that sorrow is the fruit of rajo guna (quality of passionate activity). He has also shown that only the person who recognises this truth and removes rajo and tamo guna (quality of sloth and inertia) from the heart, can be happy. As man has all the three gunas in his heart, he is bound. A farmer who wants to raise a crop in the field, at the outset, has to remove weeds from his field. If different types of weeds grow, the crop will be affected adversely. Removing the weeds is an essential precondition for getting a good crop. In the same way, a sadhaka (spiritual aspirant) who wants to realise 'atmananda' (joy of Atma), has to remove from the heart, various manifestations of rajo and tamo gunas in the form of malice, desire, greed, anger, hatred and jealousy. These six types of enemies of man are the children of rajo and tamo gunas. We won't be able to experience the joy of Atma (individual soul) as long as these weeds are there. (Divine Discourse, Sep 12, 1984)