1 Gita Sloka Every Day - Chapter 13 - Kshetra Kshetrajna Yoga - Sloka 30

The entire content of this mail is from Swami Adidevananda's translation of Ramanuja's  Gita  Bhashya and Swami Chidbhavananda's Bhagavad Gita, both published by Ramakrishna Mission

the relationship between Kshetra and kshetrajna is explained further in this stanza

Karma Pertains to Prakriti 29-30

1 Gita Sloka  Every Day - Chapter 13 - Kshetra Kshetrajna Yoga - Sloka 30

Yada bhoot pruthak bhavam eka stham anupashyati I

Tata eva cha vistaram brahma sampadyate tada II sloka 30

यदा भूत पृथक् भावम् एक स्थम् अनुपश्यति I 

तत एव च विस्तारम् ब्रह्म संपद्यते तदा II  श्लोक 30

Because he who sees the Lord, seated the same everywhere, destroys not the self by the self, therefore he reaches the supreme goal.

The wave, the billow, the ripple, the tide, the breakers, the froth - all these modifications belong to the sea. The potentiality the sea expresses itself in all these forms, which have no existence independent of the sea.

When he perceives that these diversified modes of existence of all beings as men, divinities etc., are founded on two principles of Prakriti and Purusha; when he perceives that their existence as divine, human, tall or short etc.is rooted in one common foundation, namely in the prakriti and not in the self; when he sees that their 'expansion', i.e, the successive proliferation into sons, grandsons and such varieties of beings, is from prakriti alone - meaning that he realises  the  self  devoid of limitations, in its pure form of knolwedge.