Field and knower of the field

We have to learn about field and knower of the field.my guru st nikka singh ji used to say that this chapter of Geeta is very important.we must learn about this subject.
He used to say that you are self,Atma but you identify yourself with with body,mind, intellect sense organs.this is our habit from beginning that we identify with these things.This is called in the language of vadanta 'TDATMA'.you say i do this and that.I am sad ,i am happy but you do not know that mind is sad and the 'I'is the watcher of sadness and happiness.
You can see in yourself that there is someone which remains separate from this whole business. activities of the body,activities of the mind activities of sense organs,which is changeable that all is described as known.but which remains unchangeable that is your self,knower.in 24hours our body and mind,intellect sense organs are changeable but not the seer.that which is changeable is called ksetram[field,known].As in the field we sow seed and after some time we harvest it.likewise in this body we sow seeds of our karmas[deeds].Good deeds gives us good fruits and bad actions bad fruits.this according to our past lives and in this life.we becomes rich poor,happy,unhappy according these deeds.So this body is 'ksetram'[field].but one thing more who knows the field,knower of the field that is called ksetrajna your self.that is one in all beings.that is our master,god self as you like to say.now lord krishana describes you know 'me'not body but ultimately truth and you also are'that'but you do not know due to illusion .Lord krishana says that that the knowledge of the knower of the field and the field is real knowledge according my my views.as has been suggested by lord krishana-continue