Bhagavad-gītā is also known as Gītopaniṣad. It is the essence of Vedic knowledge and one of the most important Upaniṣads in Vedic literature.
Bhagavad-gītā is a treatise which is especially meant for the devotee of the Lord. Bhagavad-gītā should be taken up in a spirit of devotion. Unless one reads the Bhagavad-gītā in a submissive spirit, it is very difficult to understand Bhagavad-gītā because it is a great mystery.
The purpose of Bhagavad-gītā is to deliver mankind from the nescience of material existence. Every man is in difficulty in so many ways, as Arjuna also was in difficulty in having to fight the Battle of Kurukṣetra. Arjuna surrendered unto Śrī Kṛṣṇa, and consequently this Bhagavad-gītā was spoken. Not only Arjuna, but every one of us is full of anxieties because of this material existence. Our very existence is in the atmosphere of nonexistence. Actually we are not meant to be threatened by nonexistence. Our existence is eternal. But somehow or other we are put into asat.
Humanity begins when this sort of inquiry is awakened in one’s mind. In the Brahma-sūtra this inquiry is called “brahma-jijñāsā.” Every activity of the human being is to be considered a failure unless he inquires about the nature of the Absolute. Therefore those who begin to question why they are suffering or where they came from and where they shall go after death are proper students for understanding Bhagavad-gītā.
From Bhagavad-gītā we must learn what God is, what the living entities are, what prakrti is, what the cosmic manifestation is and how it is controlled by time, and what the activities of the living entities are.
Vedic knowledge is complete because it is above all doubts and mistakes, and Bhagavad-gītā is the essence of all Vedic knowledge.
One cleanses himself daily by taking a bath in water, but one who takes his bath only once in the sacred Ganges water of the Bhagavad-gītā cleanses away all the dirt of material life. Because Bhagavad-gītā is spoken by the Supreme Personality of Godhead, one need not read any other Vedic literature. One need only attentively and regularly hear and read the Bhagavad-gītā.