Lord Krishna is dealing with the topic of jñānam from verses 8 to 12.  In this context jñānam means all the virtues of mind which are conducive to the attainment of knowledge.  In the 11^th verse, Lord Krishna emphasizes the importance of Bhakti.  Jñānam is only possible with the bhakti.  Karma yoga, upasana yoga and jñāna yoga all are bhakti yoga.  When Krishna prescribes bhakti as a necessity, it is not jñāna bhakti as this is a sadhana to becomes a jnani.  Artha bhakti is only conducive for worldly goals.  Here the goal is God and not a means to worldly end.  So, this bhakti can only be jigyasu bhakti.  We should have the maturity enough to know that everything other than God is perishable and god alone can give me security and completeness.  This devotion to God must be undivided.  Even when the worldly transactions are going on, this devotee must remember that the purpose of life is poornatvam. 

The next virtue are.

1. Viviktha desa sevitvam:  Resorting to a secluded place; resorting to solitude; this is also expression of samsara; Developing a habit of going to a secular place of solitude and find out whether I can confront myself.  One version of samsara is the fear of solitude or loneliness   This is the other purpose of this solitude is to face loneliness.  This will also help to gracefully handle old age.
2. Tattva jñānam artha darshanam:  Knowing value for Jñānam; knowing the benefit or the value of Jñānam. We should know what we will get out of this knowledge.  Regularly remind us that jñānam gives inner peace and inner freedom.
3. Adhyatma Jñāna nithyātvam:  Systematic and consistent study of Vedantic scriptures for a length of time under the guidance of a competent acharya.  Without systematic study, we will get only a few ideas.  The word sravanam presupposes study of the scriptures under a competent acharya.  This guru should deal only with sastra.  All other virtues prepare the student and this virtue provides the knowledge.

These 20 virtues together with satvic study will lead to gyanam.  Opposite of all these virtues is ajñānam.  Negative virtues will solidify ignorance. 

Verse 13:

I shall teach you that which is to be known, upon knowing which one attains immortality.  It is the supreme Brahman which is beginning less.  It is said to be neither and effect nor a cause

Arjuna wanted to know about six topics.  Now Krishan takes up the topic of Jñeyam in verse 13 to 19. Jñeyam is same as kṣetram. This subject matter everyone should know because this solves the fundamental and universal problem of insecurity that every human being suffers.  The ultimate thing to be known is brahman.  Brahman is free from three limitations:

1. Space limitation (can only be in one place),
2. Time Limitation.  We have a date of birth and date of death.
3. Attribute limitation.  Presence of one attribute, excludes all other attributes; One color excludes all other colors.

Brahman is free from all the three limitations; Any cause is in potential form, but it is not available for use,  so  it is as though does not exist, and it is called asat.  Everything we see and experience is the result of cause-and-effect flow.  The difference between kariyam and karanam is time.

Brahman is beyond time, space and attribute and is beyond the realm of cause and effect.