Just like Kṛṣṇa is teaching Arjuna. Before this, Kṛṣṇa (Arjuna) surrendered himself: śiṣyas te 'haṁ śādhi māṁ prapannam (BG 2.7). Although they were friends, Kṛṣṇa and Arjuna were friends . . . first of all, they were talking like friends, and Arjuna was arguing with Kṛṣṇa. This argument has no value, because if I am imperfect, what is the meaning of my argument? Whatever I shall argue, that is also imperfect. So what is the use of wasting time by imperfect argument? This is not process. The process is that we must approach to a perfect person and take his instruction as it is. Then our knowledge is perfect. Without any argument.
We accept Vedic knowledge like that. For example, just like stool of an animal. It is stated in the Vedic literature that it is impure. If you touch stool . . . according to Vedic system, even after passing my own stool, evacuating, I have to take bath. And what to speak of others' stool. That is the system. So stool is impure. One, after touching stool, he must take bath. This is Vedic injunction.
But in another place it is said that the stool of the cow is pure, and if cow dung is applied in some impure place, it will be pure. Now, by your argument, you can say that, "The stool of an animal is impure. Why it is said in one place pure and another place impure? This is contradiction." But this is not contradiction. You practically make experiment.