Arjuna accepted Kṛṣṇa as spiritual master. In the beginning, he was talking like friend. Friend to friend talking, sometimes it comes to nil, no conclusion, simply waste of time. It is called vitaṇḍā. That sort of argument has no value, because it will never come into conclusion.
But when we talk with authority, the spiritual master, representative of Kṛṣṇa, then we cannot argue. We have to accept. guru-vākya. guru-vākya, you cannot deny it. It may not be agreeable to you in the beginning, but you cannot deny it. That is the system of Vedic system.
Here, Arjuna has accepted Kṛṣṇa as the spiritual master. Śiṣyas te aham: "I become Your disciple. Because we were talking till now as friends, but this will not decide the case. My case is very serious. My duty is to fight, but I do not like to fight. Some affection, some family relationship, is deterring me to fight, making me coward.
So therefore it is a very complex position. And I find that You can make a solution of this complex position. I therefore accept You as my spiritual master, and I fall down under Your lotus feet as Your disciple." Śādhi māṁ prapannam. "I am surrendered. Now You kindly protect the surrendered soul."
So here Kṛṣṇa is instructing. First of all, He chastised Arjuna, aśocyān anvaśocas tvaṁ prajñā-vādāṁś ca bhāṣase (BG 2.11): "My dear Arjuna, you are talking like a very learned man, but I find that you do not know in which case you have to lament and in which case you have to joyful. That you do not know."
Gatāsūn agatāsūṁś ca nānuśocanti paṇḍitāḥ. Indirectly He said that, "You are not paṇḍita; you are a fool, because you are arguing in this way that, 'If I kill my brothers, their wives will be widow, and they will become prostitute and there will be varṇa-saṅkara.' "
These questions are very nice. If women become prostitute, then the population is varṇa-saṅkara. And varṇa-saṅkara means unwanted children. They become practically nuisance in the society. Narakāyate. If varṇa-saṅkara population is increased, then the whole society becomes a hell. That's a fact. Actually, that is the position at the present moment.
Therefore, according to the Vedic system, marriage is there. Without marriage, the population, increase of population, means varṇa-saṅkara. So these things were discussed, but that was not the main case. The main case was whether Arjuna was to fight and to kill the other party. He was thinking very serious.
So Kṛṣṇa in the beginning said that, "You are lamenting on the point that your brothers, your grandfather, they will die." That is the general impression of the people, that "I die. You die." But Bhagavad-gītā says, na hanyate hanyamāne śarīre (BG 2.20): nobody dies, even after the destruction of this body. This is the beginning of that instruction. Na hanyate hanyamāne śarīre. We are eternal. Nityaḥ śāśvato 'yam, na hanyate hanyamāne śarīre.
Now where is the knowledge? We are traveling all over the world. We have never seen any university or any department of knowledge where this technique is instructed, na hanyate hanyamāne śarīre. There is no such instruction. So just try to understand, in the name of education, how people are placed in ignorance. They are thinking that, hanyamāne śarīre, hanyate: after killing the body, the body's finished, the man is finished.
I was talking with a big professor in Moscow, Professor Kotovsky. He said: "Swāmījī, after destruction of this body, there is nothing more. Everything is finished." So just see, a big professor, a responsible person, he has no knowledge about the soul, what is soul, what is body. He's superficially, he is studying that after this body is finished, everything's finished. But that is not the fact.