In this 13^th chapter, Arjuna asked for clarification of six concepts:

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

Krishna now addresses jñeyam or Brahman in verses 13 through 19^th.  In this context jñeyam means param brahman.  Jñeyam, Brahman is the ultimate truth everyone should know.

Krishna is revealing Brahman as pure existence.  Existence and consciousness are two subtle concepts which have different meanings than what we usually we think of.  According to vedanta, existence is the unique and all principles we talked about consciousness can be extended to existence.  All these five principles must be extended to existence also because existence is same as consciousness. 

1. Existence is not a part, product, or property of the body of any object.
2. Existence is an independent entity and is the ultimate substance, which pervades the body and makes it existent.
3. Existence extends beyond the body or object.
4. Existence survives the fall of the body or object.
5. The surviving Existence is not recognizable, not because it is not there, but because of the absence of reflecting or manifesting medium.

This pure existence is pure consciousness, that pure consciousness is Brahman, and that pure consciousness is you – Tat Tvam Asi.  Pure existence can never be understood – it can only be understood along with an object.  Similar to when you ask for water, it is understood that a cup is needed to transport water.

The existence’s manifestation is recognized through every sense organ.  In and through every sensory perception, existence is recognized. At the same time, the existence or Brahman is free from all the sense organs; they are not intrinsic nature of Brahman.  Similar to hand being not part of light.  You appreciate the world through existence, but world is not a part of Brahman.  This existence Brahman supports everything, because of Brahman alone every object enjoy existence.  Brahman is free from all the objects of the world. 

Existence is associated with every object, but not affected by any objects.  Similar to all characters of a movie are associated with the screen, but the screen is not affected by the characters of the movie.  Brahman is nirgunam.

Verse 16

It is outside and inside beings.  It is unmoving and moving.  It is far and near.  Being subtle, it is unknowable.

The existence Brahman is both inside outside the body and objects, similar to the light is upon the hand as well as outside the hand in unmanifested form.  Consciousness is in this body; consciousness is other bodies and consciousness is also in between the bodies.  You can never think of absence of existence anywhere. 

It is moving and it is nonmoving.  It is really non-moving, but it is seemingly moving when the medium moves.  Moving property of an object is transferred to existence.  For example, the rotation of the earth is attributed to the sun, and we say sun rises and sets, but the sun does not rise and set. 

For a wise person, Brahman is the nearest – is one with me.  For an ignorant person, Brahman is far away, because he continues the search for Brahman.  If Brahman is everywhere, why don’t I recognize that Brahman?  Even though Brahman is everywhere, Brahman is free from attribute, and we can’t recognize an object if it does not have any attribute.  Attributes alone help me recognize.  We recognize objects by color, form etc.  The less the number of attributes an object has, the more incomprehensible the object is. 

• Prithivi is the grossest thing we can recognize – it has all five attributes – smell, taste, sound, touch, and form.
• Water does not have the attribute of smell, but has the other four – taste, sound, touch and form. 
• Agni has three attributes – sound, touch and form, but does not have the attributes of smell and taste.
• Vayu has two attributes, sound and touch and not form, smell and taste.
• Akasa has only one attribute – sound, the echo capacity.

Verse 17

Moreover, it remains undivided.  Yet it appears as if divided in beings.  That Brahman is the creator, the destroyer, and the sustainer of all beings.

Brahman is indivisible, like space which can’t be divided.  At the same time, it is seemingly divided.  It is in every body, but also in between the bodies.