This past, present and future, knowledge, how Kṛṣṇa knew, that was also proved. When Kṛṣṇa said that, "I spoke this philosophy to Vivasvān . . ." Vivasvān means to the sun god, in the beginning, before Manu. That means about forty thousand millions of years ago, according to Manu-saṁhitā. Then Arjuna inquired, "My dear Kṛṣṇa, we are contemporaries. We are born some years ago. How is that—You instructed the sun god, Vivasvān, this philosophy?" This inquiry was made by Arjuna. Why? How Kṛṣṇa knows the past so long, long years ago? So Kṛṣṇa replied that, "Yes, at that time you were also present, but you have forgotten. I have not forgotten."
That is the difference between ordinary human being and God. That is the difference. God does not forget past, present, future. God knows future. God knows past. And present, what to speak of? In the Second Chapter you'll find also. Kṛṣṇa says that, "It is not that you, Me and all these kings and soldiers were not existing in the past. And we are existing at present. And it is not that we shall not existed in the future." These are the things.
So if you try to understand Bhagavad-gītā as it is, then we get some benefit. Not some benefit, the ultimate benefit. What is the purpose of Bhagavad-gītā? Kṛṣṇa has come. Kṛṣṇa's instructing Arjuna. Aiming at Arjuna, He's instructing the whole world—what is the position of the living entities, what is our constitutional position?
We are all living entities, and Kṛṣṇa is God. What is Kṛṣṇa's position? What is our position? What is this material nature? What is the time factor? What is our activities? These things are very nicely explained. Prakṛti, puruṣa, jīva and time and karma. These five things are very nicely described.