Bhagavad Gita Verse 16, Chapter 13

avibhaktam cha bhooteshu vibhaktamiva cha sthitham |
bhootabhartri cha tajjneyam grasishnu prabhavishnu cha || 16 ||
 
And undivided, yet it exists as though divided in all beings. That, which is to be known, is the nourisher of beings. It is the devourer, and it is the creator also.
 
avibhaktam : undivided
cha : and
bhooteshu : all beings
vibhaktam : divided
eva : as though
cha : and
sthitham : exist
bhootabhartri : nourisher of beings
cha : and
tat : that
jneyam : to be known
grasishnu : devourer
prabhavishnu : creator
cha : and
 
Shri Krishna continues to elaborate upon the topic of jneyam, that which is to be known, which is brahman, the eternal essence. Here he further describes the distortion created by upaadhis or conditionings in our understanding of the eternal essence. He begins by asserting that the eternal essence is undivided, it is unbroken and continuous. It cannot be chopped up into pieces. But due to the effect of space as an upaadhi, it appears as if the eternal essence exists differently in various beings.
 
We can go back to the example of the clay pot and space. If we have a hundred pots on the floor, it appears as though the space in the room is divided into a hundred “pot-spaces”, due to the boundary created by the wall of each pot. But in reality, space can never be divided or chopped up. Or we can also look at the example of electricity, which looks like it functions differently in each appliance, but is really one continuous circuit that begins at the power plant. If our senses cannot access upaadhis such as pots or appliances, they mistakenly assume that subtle things such as space and electricity are absent. Similarly, the body of a living entity serves as an upaadhi where we can feel the presence of the eternal essence.
 
So if there is only one continuous and undivided eternal essence, how do we account for all of the creation, sustenance, and destruction of names and forms in the universe? Shri Krishna says that ultimately, it is the eternal essence that provides the foundation for the lifecycle of the universe. Waves are created, sustained and dissolved back into the ocean. If we pay attention to the waves, we lose sight of the ocean that is one undivided foundation which is behind all of the waves. We come back to the same point again : the eternal essence provides existence, the “is-ness”, to all names and forms in the universe.
 
Now, if the eternal essence cannot be comprehended by the senses, is it dark and empty like a black hole? This is clarified in the next shloka.