yatha prakasayaty ekah
krtsnam lokam imam ravih
kshetram ksetri tatha krtsnam
prakasayati bharata

"O son of Bharata, as the sun alone illuminates all this universe, so does the living entity, one within the body, illuminate the entire body by consciousness."

Bharata = descendent of Bharata dynasty [Arjuna], yatha = just as, ravih = the Sun, ekah = being single, imam lokam = all these [objects] seen, krtsnam = without exception, prakasayaty = are illuminated. The single Sun, is able to illuminate any and every object seen on this earth, without exception by its rays. Our atman is now compared to Sun and all our organs are comared to the objects on earth and the Gyana is compared to the rays fom Sun. Orgnas and objects are many. Gyana and rays are in abundance. But Sun and atman are single. Kshetram = body [and associated organs], ksetri = atman [inside body], tatha =similarly, kritsnam = without exception, prakasayati = is able to perceive. Here we should not misunderstand that a single atman is understanding all bodies, but atman is able to perceive all organs in the body in which it is resident. Atman is able to know about all the parts and their activities, in the body in which it is resident. Could this sloka mean, that just as Sun illuminates all objects we see, an atman is illuminating all organs? But this is not the topic the Lord has been telling Arjuna all along. We should understand that just as the luminous Sun is different from the illuminated world, similarly, knowledgeable atman is different from the body to be known. Knower is atman and object of knowing is body. Atman is without organs and body is with organs. Another point also we should understand is that one atman is not knowing all bodies but each atman knows about each body, in which it resides. How such minute atman, residing in one corner of our heart is able to know about the entire body, which has innumerous parts? Like the radiance of the Sun, it is the Gyana of atman which is able to know all. This Gyana tells that all parts are belonging to atman, when we say, 'my hand, my head, my foot, etc.'. Thus we know the difference between body and soul. In fact it is Sri Narasimha, Who teaches us unity in diversity. He possesses Lion's head and human body; yet, He is One. This is His capability.