16.21: There are three gates leading down to hell; these are lust, anger, and greed. Every sane man should, therefore, give up these three things.
22: One who is freed from these three gates to hell, O son of Kunti, performs good for his self-realization, and thus gradually attains to the Supreme destination.
ONE SHOULD BE VERY careful of these three enemies to human life: lust, anger, and greed. The more a person is freed from lust, anger, and greed, the more his existence becomes pure. Then he can follow the rules and regulations enjoined in the Vedic literature. And, by following the regulative principles of human life, he gradually raises himself to the platform of spiritual realization. If one is so fortunate, by such practice, to rise to the platform of Krishna consciousness, then success is guaranteed for him. In the Vedic literature, the ways of action and reaction are prescribed just in order to come to the stage of purification. The whole method is based on the giving up of lust, greed, and anger. By cultivating knowledge of how to do this, one is elevated to the highest position of self-realization; and thus self-realization is perfect in devotional service. In that devotional service, the liberation of the conditioned soul is guaranteed. Therefore, according to the Vedic system, there are instituted the four orders of life and the four social ranks called the spiritual order system and the caste system. There are different rules and regulations for different castes or divisions of society; and if a person is able to follow them, he will be automatically raised to the highest platform of spiritual realization. And then he can have liberation without any doubt.