So, tat kṣetraṁ…
So, now Sri Krishna expounds the idea of kṣetra, starting with body, now He expounds it and says:
tat kṣetraṁ yac ca yādṛk ca yadvikāri yataś ca yat |
sa ca yo yatprabhāvaś ca tat samāsena me śṛṇu ||3|| (XIII)
“What is that kṣetra? What is his nature? What are his modifications? yadvikāri, What are the transformations of that? Form where it comes? yataś ca, from where these transformations come? sa ca yo yatprabhāvaś ca, what are the effects of these modifications? tat samāsena meśṛṇu, that in fullness you listen from Me.”
In between there is the 2nd verse, (I went to the 3rd because I had to expound the idea of kṣetra), which is explained in the 1st and the 3rd verse. In the 2nd verse we have now the concept of kṣetrajña, who is the knower of the field:
kṣetrajñaṁ cāpi māṁ viddhi sarvakṣetreṣu bhārata |
kṣetrakṣetrajñayor jñānaṁ yat taj jñānaṁ mataṁ mama ||2|| (XIII)
Who is the kṣetrajña? In the first place we only said that one who observes, one who knows the body is the knower. Now, Sri Krishna expounds the idea further and expounds it: māṁ viddhi, who is the knower? The knower is Me, the supreme Lord Himself is the Knower; the whole world as it appears to us is the kṣetra and the kṣetrajña is the supreme Lord; kṣetrajñaṁ cāpi māṁ viddhi, you realise Me as the kṣetrajña, one who knows the kṣetra; sarvakṣetreṣu bhārata, He is in all the fields whether is that body, or in that body, or in any body, everywhere there is one knower and that is Myself, the supreme Lord.
kṣetrakṣetrajñayor jñānaṁ yat taj jñānaṁ mataṁ mama, the true knowledge is nothing but the knowledge of kṣetrakṣetrajña: ‘when you know the field and the knower of the field, when both are known, then that is the true knowledge’. Merely knowing the field is never the knowledge of the field unless you know the kṣetrajña: the more you know yourself, the more you know the field, the key is in the kṣetrajña. If you don’t know the eyes you cannot even know the world: the eyes are the key to the knowledge of the world; the more your eyes are luminous, the greater is the luminosity of the world; the eyes are the knowers. So, the more you know the knower, the more you know the kṣetra, the world.
You will see here the psychology of knowledge and the epistemology of knowledge. What is it that can be called knowledge? How do you know that knowledge is knowledge? Why should you call something to be knowledge and something not to be knowledge? What is the characteristic of it? You will see that this question was never raised in all these 12 chapters, it is as if at a very subtle level you are taken up into the profoundest levels, the root-question of all knowledge is raised and answered.
So, He says: what is the definition of knowledge? kṣetrakṣetrajñayor jñānaṁ, the knowledge both of the field and the knower of the field, when both are combined together, the knowledge of this harmony between the kṣetra and the kṣetrajña, then you can say this is knowledge: if you know only kṣetrajña it is not knowledge, if you know only the kṣetra it is not knowledge, it is when the two are united together and you know both of them, then that is knowledge.
So, now comes the exposition of the kṣetra, and it is that which is now described in the verse n°4 onwards:
ṛṣibhir bahudhā gītaṁ chandobhir vividhaiḥ pṛthak |
brahmasūtrapadaiś caiva hetumadbhir viniścitaiḥ ||4|| (XIII)
ṛṣibhir bahudhā There are many Rishis who have described this kṣetra; chandobhir in many verses of inspired scripture, in the Vedas and the Upanishads; vividhaiḥ gītaṁ, in many form it has been described; then, when you come to brahmasūtra, if you look at the terms of brahmasūtra, then, in detail in a philosophical manner, hetumad, in a philosophical exposition, you will find about this kṣetra in detail: that is by the Vedas, Upanishads and Brahmasutra, if you refer to these three, you get a detail knowledge of this field.
But, Sri Krishna now describes all that knowledge in a few words, like a summary of all that. What is that field?
mahābhūtāny ahaṅkāro buddhir avyaktam eva ca |
indriyāṇi daśaikaṁ ca pañca cendriyagocarāḥ ||5|| (XIII)
icchā dveṣaḥ sukhaṁ duḥkhaṁ saṅghātaś cetanā dhṛtiḥ |
etat kṣetraṁ samāsena savikāram udāhṛtam ||6|| (XIII)
etat kṣetra, this is the field, (this is the 6th verse) etat kṣetraṁ this is the field, samāsena in this totality, savikāram with all its modifications, udāhṛtam illustrated, expounded. “It is that field which in its totality explain with all its modifications”.