Lord Krishna said: O Kaunteya (Arjuna), this body is called kshetra, the Field. Knowers of Truth say that whoever knows this, is the Kshetrajña, the knower of the Field.
The dialogue is entering a new phase of enumerations, making the subject of spiritual knowledge lucid and more sādhanā-oriented.
Of the three broad sections of the Text, thirteenth chapter marks the beginning of the third dealing with the subject of spirituality in greater depth and detail. Arjuna’s enquiry provides a new focus for Krishna to speak on. Prakrti is the changeful material part of Creation, and Purusha, the non-changing conscious substratum. Arjuna also wants to know the Knower (Kshetrajna) as distinct from the Field of activity (kshetra), and also the knowable (jneyam) as distinct from knowledge (jnānam).