So in this Bhagavad-gita the subject matter comprehends about the īśvara, the supreme controller, and about the controlled living entities and prakṛti, the nature, the material nature. And next, the time, or duration of existence of the whole universe, or this manifestation of the material nature, and the duration of time, or the eternal time, and karma. Karma means activity. Everything, the whole universe, whole cosmic manifestation is full of different activities. The living beings especially, they are all engaged in different activities. So we have to study from the Bhagavad-gītā, īśvara, what is God, jīva, what are these living entities, and prakṛti, what is this cosmic manifestation, and how it is controlled by time, and what are these activities?
Now out of these five subject matter, in the Bhagavad-gītā it establish that the Supreme Godhead or Kṛṣṇa or Brahman or Paramātmā... You may call whatever you like. But the supreme controller. There is a supreme controller. So the supreme controller is the greatest of all. And the living beings, they are in quality like the supreme controller. Just like the supreme controller, the Lord, He has control over the universal affairs, over the material nature, how the... It will be explained in the later chapters of Bhagavad-gītā that this material nature is not independent. She is acting under the direction of the Supreme Lord.