Arjuna asked for the clarification of six technical terms.  The six terms are:

1. Prakriti
2. Purusha,
3. kṣetram,
4. kṣetrajña  
5. jñeyam.
6. jñānam

Lord Krishna takes up the two words kṣetram and kṣetrajña.  The word kṣetram means the entire objective universe experienced by us.  It includes the world, the body and mind.  Among these three, the world is away from us and the body/mind is intimately associated with me the observer.  So, the body and mind appear to be integral part of me. 

An object which serves as an instrument is integrally connected to the subject and we include that with the observer.  Similar to how we include spectacles as part of us.  Similarly, body and mind are instruments, but they appear to be an integral part of the observer.  But both of them should be included in kṣetram, the objective universe consists of three: Body, mind and universe.  Kṣetrajña is different than the body but makes the body an enliven body.  The principle behind kṣetram is kṣetrajña.  We should understand that an individual is a mixture of body and consciousness or dheha and dhehi or atma and anatma.  Generally, we tend to identify with the body only.  After the study of vedanta, we say that we are body and behind the body there is an eternal consciousness or atma.  That is not the right approach.  The right approach is saying that I am the consciousness and body is only an incidental medium through which we transact with the world.   We are using the body temporarily and should be willing to give it back to the world.  This shift of identification from kṣetram to kṣetrajña called aparoksha jñānam.    

Verse 3

Oh Arjuna! Moreover, know the kṣetrajña to be Myself, obtaining in all bodies.  The knowledge which deals with kṣetram and kṣetrajña is true knowledge.  This is My teaching.

The steps in understanding ourselves:

1. First, we identify ourselves with body and say I am the body.
2. Then we say that I am the body backed by consciousness.
3. Then we say I am not the body with consciousness, but I am the consciousness with an incidental body.
4. Finally, we say I am the consciousness not only behind my body but also the consciousness behind every body.  The consciousness is also there in between the bodies.  The consciousness in between the bodies is not recognizable because there is no medium to transact the consciousness.  Consciousness pervades everywhere.  Wherever body is there, consciousness manifests itself and wherever body is not there, consciousness does not manifest itself.

Consciousness has two names.  From the standpoint of a single body or individual body, it is called jivatma.  The very same consciousness from the standpoint of all the body or totality, it is called paramatma.  From a micro standpoint it is jivatma and from the macro standpoint it is paramatma.  If you negate micro and macro, it is atma.  Jivatma is atma, paramatma is atma, both are essentially the same.  This recognition is jivatma paramatma aikya Jñānam.  This is similar to wave and ocean; they both are water only and the wave and ocean are different names and forms given to water.  The containers (different bodies) are different, but the content is only one atma.   This is the real knowledge that must be acquired by everyone.  This is para vidya and all other knowledge are apara vidya.  Shankaracharya boldly says apara vidya is ignorance. 

How does this knowledge change our lives?  Consider two waves; one wave knows that I am the wave; the other wave knows that it is water.  The first wave keeps growing as it approaches the shores, but it knows that it will be no more when it reaches the shore.  As long as it thinks itself as wave, it can’t evade this insecurity.  But the second wave knows that the wave is only a name and form but in reality, it is water and therefore does not have the same insecurity.  Similarly, as long as we consider ourselves as the mortal body, there will be insecurity.  When we see ourselves as atma, that knowledge will give security.  All other knowledge only will give only a false sense of security.

But we must note that vedanta does not give security; Vedanta removes the sense of insecurity by revealing that you don’t need any support from outside to be secure.

Verse 4

What is kṣetram?  Of what nature is it?  Of what effects is it?  Which effect comes out of which cause?  What is that kṣetrajña.  And of what glory is it?  Hear that from me briefly.

In the previous two verses, Krishna briefly described kṣetram and kṣetrajña.  In this verse, he elaborates the following:

What is kṣetram?

What is the nature of kṣetram?

What are the causes of kṣetram?

What are the effects of kṣetram?

Krishna also elaborates kṣetrajña.

What is kṣetrajña or consciousness?

What are the glories or features o kṣetrajña?

A scientist says consciousness is that which is not subject to the laws of creation and it does not have a physical location; it is beyond time and space.