At the end of 7th chapter, Lord Krsna mentioned some terms which become questions of Arjuna in this 8th chapter.
kim tadbrahma kimadhyātmam kim karma purusottama |
adhibūtam ca kim proktam adhivaivam kimucyate ||8.1||
What is that Brahman; what is centred on the self; what is karma, oh Purusottama, and what is spoken of as centred on the beings; and what is it that is said as centred on the gods?
adhiyajñah katham ko'tra dehe'smin madhusūdana |
prayānakāle ca katham jñeyo'si niyatātmabhih ||8.2||
How and who is that centred on ritual here in this body; oh Madhusūdana, and at the time of death, how are you known by those whose minds are steady?
Seven questions are asked by Arjuna, they are:
What is that Brahman?
What is adhyātma?
What is karma?
What is adhibhūtam?
What is adhidaivam?
What is adhiyajñah?
How does one with steady mind remember Īśvara at the time of death?
Lord Krsna answered six questions of Arjuna briefly in third and fourth sloka.
Aksaram brahma paramam svabhāvo'dhyātmamucyate |
bhūtabhāvodbhavakarah visargah karmasamjñitah ||8.3||
Brahman is limitless and not subject to change. What is centred on oneself is called one's nature. What is known as karma is an offering which causes the production of bodies for the beings.
1. What is that Brahman? Aksaram brahma paramam - that which is imperishable is Brahman. Aksaram means that which does not decline. Anything that declines is within time and therefore subject to all the six-fold modification. So what doesn't decline is also free from these modifications, therefore it is imperishable. Only those which is born will go through modification and lastly perishes. Being imperishable, it is paramam - unsurpassable, not conditioned by place, time, or any given attribute.
2. What is adhyātma? svabhāvo'dhyātmamucyate - Adhyātmā is said to be one's own nature. Ātmā here means body, so adhyātma means what is centred / obtained in the physical body. That is cit- consciousness, Brahman. Brahman which is obtained in every individual body is called adhyātma. The meaning of Brahman and adhyātma are identical but are used in different contexts. Brahman is used only when we talk about the cause of the world. That Brahman is equated to this jīva/individual who is adhyātma, centred on a given physical body. Lord Krsna said, "the wise man knows Brahman", means jñāni knows Brahman not as another object/entity, but as himself/herself, therefore the word adhyātma is used for the equation.
3. What is karma? visargah karmasamjñitah - what is known as karma is visarga - offering. The meaning of karma here is offering intended for a given devatā - deities in the ritual, by extension all activities which cause punya and pāpā. Karma which is bhūtabhāvodbhavakarah - that which causes the birth of beings. Therefore karma is offering / action which causing unseen result which is the cause for being born. Karma also is not separated from Brahman, because the action, the agent, and all other things connected to the action are Brahman himself as we saw in the fourth chapter 4.24.
adhibhūtam ksaro bhāvah purusaścādhidaivatam |
adhiyajño'hamevātra dehe dehabhrtām vara ||8.4|| What is centred on the beings is the one subject to decline and what is centred on the devatās is Hiranyagarbha; I alone am what is centred on ritual, here in this body, for the one who has body, oh most exalted one (Arjuna).
4. What is adhibhūtam? adhibhūtam ksaro bhāvah - all existing beings are subject to change. Whatever is born (comes to being) including the entire world is called adhibhūtam. Because they exist in time therefore they are subject to changes. This adhibhūtam is Brahman alone. Because for their existence, sat - existence Brahman is there as the basis to support. When there is changes, it depends upon a changeless basis. Any given object is subject to change, but its essence (sat - existence) is never destroyed. And that is Brahman.
With reference to the person who is making an inquiry it is adhyātma, and with reference to all other bodies one confronts, it is adhibhūtam. There is no different between them.
5. What is adhidaivam? purusaścādhidaivatam - adhidaivam is nothing but purusah. Purusa means that by which everything is filled, the one who identifies with all the devatās, Hiranyagarbha - the total consciousness associated with the total subtle body (total mind/knowledge). He is the one who is blessing all organs of all living being. In the form of different deities, he blesses different organs. Therefore Brahman is that which centred on god, who blesses everything here.
6. What is adhiyajñah? adhiyajño'hamevātra dehe dehabhrtām. Yajñah is a ritual, and adhiyajñah is that which is centred on the ritual, which is the agent who does ritual. Ritual is there only because of the will of the ritualist. Lord Krsna said adhiyajñah is aham eva - me alone - īśvarah - the total consciousness associated with the total universe in potential form. This consciousness we can find in the body of the ritualist here (and all being), therefore he is called as dehabhrtām - the one who sustains the body.