The Lord advised Arjuna to regulate the senses from the very beginning so that he could curb the greatest sinful enemy, lust, which destroys the urge for self-realization, and specifically, knowledge of the self. Jnanam refers to knowledge of self as distinguished from non-self, or, in other words, knowledge that the spirit soul is not the body. Vijnanam refers to specific knowledge of the spirit soul and knowledge of one's constitutional position and his relationship to the Supreme Soul. It is explained thus in the Srimad-Bhagavatam: jnanam parama-guhyam me yad-vijnana-samanvitam / sarahasyam tad-angam ca grhana gaditam maya: "The knowledge of the self and the Supreme Self is very confidential and mysterious, being veiled by maya, but such knowledge and specific realization can be understood if it is explained by the Lord Himself." Bhagavad-gita gives us that knowledge, specifically knowledge of the self. The living entities are parts and parcels of the Lord, and therefore they are simply meant to serve the Lord. This consciousness is called Krsna consciousness. So, from the very beginning of life one has to learn this Krsna consciousness, and thereby one may become fully Krsna conscious and act accordingly.