Prabhupāda: This is very nice. If one can understand the principles of appearance and disappearance of God, His activities, so simply by understanding these principles he will be liberated. It is said here that after quitting this body, he is no more coming to take birth again in this material world. So just like a layman does not know how the sun appears and disappears, but an astronomer, he knows very well the movements of the sun, moon, and other planets' appearance and disappearance. This is a science, astronomy. Similarly, there is a science of God by which you can understand how God appears, disappears, how He acts, how He works. Everything is there, but if you are not interested that does not mean that the science of God is false or there is no such science. There is. You must be interested to know; then you can understand. And if you simply understand this science, then you become liberated. It is open order. Simply by understanding, even not engaging yourself in transcendental service of the Lord, simply by understanding the process of appearance and disappearance. So why don't you try that? Go on. Purport.
Tamāla Kṛṣṇa: Purport: "The Lord's descent from His transcendental abode is already explained in the sixth verse. One who can understand the truth of the appearance of the Personality of Godhead is already liberated from material bondage, and therefore he returns to the kingdom of God immediately after quitting his present material body. Such liberation of the living entity from material bondage is not at all easy. The impersonalist and the yogi attain liberation only after much trouble and many, many births. Even then their liberation is..."
Prabhupāda: Try to understand bondage, what is bondage. We are thinking we are very, we are free. We are declaring that "We belong to the free nation" or "free community," or everyone is seeking after freedom. But nobody is free. Nobody is free. Everyone is under the stringent laws of nature. So bondage means to remain under the condition of material laws. That is called bondage.
Just like people are trying for so many years to go to the moon planet. The Russian and the American scientists are competing. But they are so bound up, they go some, say, thousands and thousands of miles up, again come back. Just see how they are bound up. You cannot go. So this is the nearest planet, and there are so many other planets also. So you cannot go by your whims or by your will. This is called bondage.
But if you become free—when you are in spiritual understanding, then you are free—then you can travel anywhere. The perfect yogi, he can travel in any planet. That is freedom. That is little freedom. We have no idea what is the freedom of the spirit soul. That we have forgotten because for, from time immemorial we have been bound up under the laws of material nature, so we do not know what is freedom. But there are information of the freedom, how a spirit soul can become free.
(Lecture on Bhagavad-Gita--4:7-10--Los Angeles--6th. January, 1969).

Devotee: "Never was there a time when I did not exist, nor you, nor all these kings. Nor in the future shall any of us cease to be (B.G.2:12)." Purport: "In the Vedas, in the Kaṭha Upaniṣad, as well as in the Śvetāśvatara Upaniṣad, it is said that..."
Prabhupāda: (correcting pronunciation) Śvetāśvatara. There are many Upaniṣads, they are called Vedas. Upaniṣads are the headlines of the Vedas. Just like in a chapter there is a headline, similarly these Upaniṣads are the headlines of the Vedas. There are 108 Upaniṣads, principal. Out of that, nine Upaniṣads are very important. So out of those nine Upaniṣads, Śvetāśvatara Upaniṣad, Taittireya Upaniṣad, Aitareya Upaniṣad, Īśopaniṣad, Īśa Upaniṣad, Muṇḍaka Upaniṣad, Māṇḍūkya Upaniṣad, Kaṭhopaniṣad, these Upaniṣads are very important. And whenever there is argument on some point, one has to give reference from these Upaniṣads. If one can give reference from the Upaniṣads, then his argument is very strong. Śabda-pramāṇa. Pramāṇa means evidence.
(Lecture on Bhagavad-Gita--2:8-12--Los Angeles--27th. November, 1968).