We have ascertained the nature of existence brahman who is the source of the entire universe, where every name and form depends upon to be exist. Lord Krsna explains further that sat brahman is all pervasive in order to negate the possibility of dependency between one entity to another.
bahirantaśca bhūtānām acaraṁ caram eva ca | sūkṣmatvāt tad avijñeyaṁ dūrasthaṁ cāntike ca tat ||13.15||
That (jñeyaṁ brahman) is outside and inside of the beings, it is that which does not move and indeed what moves. Because it is subtle, it is not known and it is far as well as near.
Jñeyaṁ brahman is both inside and outside - bahirantaśca, with reference to all beings - bhūtānām. We are always keeping the skin as the limit to differentiate what is inside as the subject - me and what is outside as the object - not me. When Lord Krsna says brahman is antaḥ - inside, means don't look elsewhere, that jñeyaṁ brahman is you alone. But he also says bahiḥ - outside, means the entire names and forms are also brahman, there is no different between the subject me and the object world.
Since we always associate consciousness with living being alone, therefore Lord Krsna says acaraṁ caram eva ca - also movable and immovable, brahman is not just manifesting in the living being but also in all the non-living being. Just because of upādhi of non-living being doesn't reflect the aspect of consciousness, like muddy water couldn't reflect light, in the same way upādhi of non-living being couldn't reflect consciousness. Brahman is said to be immovable also because being all pervading, where movement is possible only if there is absent of that entity at another point, therefore movement is impossible, yet seemingly moving when the upādhi is moving. Just like when a pot is moving, seems like the space of the pot is carried together move with the pot, but in reality there is no different between the pot space and the space outside, then where is the time for the pot space to move?
If brahman is everywhere, why can't we perceive it? Because being subtle - sūkṣmatvāt, therefore can't be known as an object - tad avijñeyaṁ. Thus brahman is far - dūrasthaṁ, if we look upon it as an object. It is also near - cāntike, or even no distance, if we know brahman is myself. If I don't recognise brahman as myself, how long will I look for it? If brahman is other than me, I may stumble upon it but what is the possibility of stumbling upon myself? One who looks for brahman is brahman alone, this is only recognised by śāstrapramānam - the means to know one's true nature is only śāstra.
When brahman exist in all living and non-living being, seems like that only brahman has become many in this creation. Therefore Lord Krsna says...
avibhaktaṁ ca bhūteṣu vibhaktam iva ca sthitam | bhūtabhartṛ ca tajjñeyaṁ grasiṣṇu prabhaviṣṇu ca ||13.16||
That (jñeyaṁ brahman) remains undivided in the beings and is seemingly divided, is the sustainer of the beings and elements, and is the devourer and the creator.
Space seems to be divided by various conditioning factors like walls of rooms, pots, etc. but it remains undivided, it is relatively all-pervasive. In the same way, existence brahman is seemingly divided - vibhaktam iva because of upādhi. This "seemingly" that makes the difference between knowledge and ignorance. This means we need to remove any divisions that may be perceived, because there are no real divisions -avibhaktaṁ. Without existence, there is no existence of any names and forms, therefore brahman is called as the sustainer of all beings and elements - bhūtabhartṛ. He is the devourer - grasiṣṇuh of the entire world, when names and forms perish, what left is only existence. When the real nature of names and forms is not different from the existence which sustains, just like the effect is non-different from its cause, therefore brahman is said to be the creator - prabhaviṣṇu.