Bhagavad-gita begins with the spiritual instruction that one is not the body but is within the body. This consciousness can be possible only if one chants the holy name of Krsna, the Hare Krsna maha-mantra, and always keeps oneself in the association of devotees. This is the secret of success. Therefore we stress that one should chant the holy name of the Lord and keep oneself free from the contaminations of this material world, especially the contaminations of lusty desires for illicit sex, meat-eating, intoxication and gambling. With determination, one should vow to follow these principles and thus be saved from the miserable condition of material existence. The first necessity is to become freed from the bodily concept of life.

From Srila Prabhupada’s purport to SB 6.2.38