jneyam yattatpravakshyaami yajjnyaatvaamritamashnute |
anaadimatparam brahma na sattannaasaduchyate || 12 ||

I will describe that which is to be known, by realizing which, immortality is attained. The supreme brahman is without beginning, said to be neither manifest nor unmanifest.
jneyam : known
yat : which
tat : that
pravakshyaami : I will describe
yat : which
jnyaatvaa : having realized
amritam : immortality
ashnute : attain
anaadimat : without beginning
param : supreme
brahma : brahman
na : not
sat : manifest
tat : that
na : not
asat : unmanifest
uchyate : said
In the beginning of this chapter, Shri Krishna set out to explain what is kshetra or the field, and what is kshetrajnya or the knower of the field. He then set to list out various aspects of the field, which are also known as upaadhis or conditionings. This list included upaadhis such as the intellect, the mind, the five elements and so on. Shri Krishna also asserted there is only one knower of the field that is limited or conditioned by all of these upaadhis. He then gave us twenty attributes that we should cultivate in order to reduce the importance we give to these upaadhis, so that we can slowly uncover and get to the kshetrajnya, the knower of the field.
After assuming that we have cultivated these twenty qualities, and consequently learned how to reduce the importance of the field in our lives, Shri Krishna now gets to the main topic of this chapter. He says that he will now reveal what is the real knowledge, what all of us should know in this world as the culmination of all of our knowledge, what is “jneyam”. We learn so many things in our life through schools, colleges, professional training, street smarts and so on. But none of them can give us immortality. None of them can give us a permanent solution from the sorrows that we experience day in and day out. Each time we leave our self and go through our senses into the world to fulfill a desire, we generate sorrow, we create “death” in each such departure.
So then, what is this immortality-giving knowledge? Shri Krishna says that it is brahman, which is the very same eternal essence that is within us, and within everything else in the universe. It is “param” or supreme, beyond which nothing else needs to be known. It is “anadimat”, eternal, without any beginning, beyond all notions of time. It is not manifest, which means it is not accessible to the senses or the mind as an object of perception or a thought. But it is also not unmanifest. For instance, our unfulfilled desires lie dormant in our unconscious mind, but do not manifest as thoughts in our mind. The eternal essence is beyond our unconscious as well.
We now see why it is so difficult to understand the eternal essence. It is not like any object or form that can be described in words. It is also not an abstract concept that can be explained through logic, or by comparing it to something else or by combining one concept with another. In earlier chapters we saw how such situations can be handled with negation. If we want to instruct someone on how to select a maroon shirt, we tell them ignore all of the other colours of shirts. The one that is left will be the maroon shirt. Similarly, the eternal essence cannot be comprehended by our mind and senses because it is beyond the mind and senses. It can only be attained through negating everything that is not the eternal essence – by negating the upaadhis or fields.
Now, in the upcoming shlokas, Shri Krishna proceeds step by step to negate the upaadhis of the eternal essence, starting with the most visible ones.