So here also, the same word is used, that Kṛṣṇa says, sa eva ayam, "This yoga system, the Bhagavad-gītā yoga system which I am now speaking to you, is very old. How old you can imagine that I first spoke it to the sun-god." If you calculate only the age of Manu, it is about forty millions of years ago. To speak the minimum. So anyway, it is very, very old. Not that it is doctrine which is presented... Just like in the modern educational system somebody is presenting some doctrine, and he's getting the title "Doctor," some new thesis. It is not like that. There is nothing to be researched. Eternal knowledge has nothing to be researched. There is no question of research. It is already established. Otherwise there is no meaning of eternal. This knowledge of Bhagavad-gītā is eternal. It is not a product of modern research or doctrine. Purātanaḥ sa eva. Sa evāyaṁ mayā te adya. Adya means "today." "Today I am speaking on the battlefield." Yogaḥ proktaḥ purātanaḥ. "Why You are selecting me? Why You are selecting me and why this battlefield? You are speaking a philosophical doctrine and the science of God, and You are speaking to me. I am not a Vedantist, I am not even a brāhmaṇa, I am not even sannyāsī. Ordinary gṛhastha. Of course, I have got the privilege that I am Your friend. So much so. Otherwise, yoga system is not to be spoken to me. Why You are speaking to me?" This may be questioned. Why specifically it was spoken to Arjuna? The reply is, bhakto 'si. "The only qualification is that you are My devotee. That's all."