Bhagavad Gita Verse 22, Chapter 13

upadrashtaanumantaa cha bhartaa bhoktaa maheshvaraha |
paramaatmeti chaapyukto dehesmin purushaha paraha || 22 ||
 
He who is the witness, the permitter, the nourisher, the experiencer, the master and who is also spoken of as the supreme self, is the supreme Purusha in this body.
 
upadrashtaa : witness
anumantaa : permitter
cha : and
bhartaa : nourisher
bhoktaa : experiencer
maheshvaraha : master
paramaatmaa : supreme self
iti : in this manner
cha : and
api : also
uktaha : spoken
dehe : body
asmin : this
purushaha : Purusha
paraha : supreme
 
Imagine that your grandfather comes to stay in your apartment for a short vacation. Seeing a new senior citizen in the building, the apartment complex association invites him to one of their cultural programs. Your grandfather thoroughly enjoys it. Next, the association asks him permission to host their next weekly meeting in your apartment, which he readily agrees to. He is so excited about the meeting that he prepares tea and snacks for them. By the next weekly meeting, he has become so involved in the association meetings that he feels the need to vote on issues that he strongly feels about. He gets so involved that it is just a matter of time before he is elected president of the apartment complex association.
 
Your grandfather, who had nothing whatsoever to do with the building, started out as a pure witness, then become the permitter, nourisher, experiencer and subsequently the master of the building association. Similarly, Shri Krishna says that the eternal essence that has nothing whatsoever to do with Prakriti, develops a strong identification with a body. By taking various upaadhis or conditionings such as the body, the mind, the vital forces, the intellect and so on, it becomes the permitter, the nourisher, the experiencer and the master of this body, just like your grandfather took on various roles as a member of the apartment complex association.
 
Practically speaking, we don’t need to worry too much about this. All that we need to know that we don’t have to go out into the world hunting for Ishvara. Ishvara is resident in our body as the permitter, nourisher, experiencer and so on. He is the paramaatmaa, the supreme self resident as the “I” in all beings. This is how we have to understand what Purusha means. The more we pay attention to the Ishvara aspect in us, the less importance we give to the upaadhis, especially the ego. People who have reached the pinnacle of their spiritual journey eventually lose their individuality and themselves become the universal witness, the upadrashtaa, remaining unaffected by the goings on of Prakriti.