In the beginning, the six chapters in the Bhagavad-gītā are simply devoted to understand what is the constitutional position of the jīva. The living entities are eternal. That is stated in the Second Chapter of the Bhagavad-gītā: dehino 'smin yathā dehe . . . (BG 2.13).
(break) . . . dvau bhūta-sargau loke 'smin daiva āsura (BG 2.13). Asmin loke, in this world, there are two kinds of living entities, not only in human society but also in animal society, in trees, in plants, in . . . there are 8,400,000 species of life—aquatic, plants, trees, reptiles, insects, birds, beasts, then human beings, civilized human beings, noncivilized human beings. And altogether, there are 8,400,000 species of life, and they are divided into . . .
(break) . . . man's body. So . . . but I am the same. I can remember some of the incidences of my childhood, of my boyhood, of my youthhood. Therefore I am permanent. That is the real understanding of the living entity. These things have been explained very vividly.
And in the Sixth Chapter Lord Kṛṣṇa recommended how to practice yoga. Yoga is the beginning of linking up our lost relationship with the Lord, yoga. Yoga means adding, addition, or linking. Because we are now forgotten . . . the yoga system, any yoga system, means . . . bhakti-yoga, karma-yoga, jñāna-yoga—there are different names of yogas—but actual fact is how to link up our lost relationship with the Supreme Lord. That is called yoga. Yoga indriya-samyamaḥ.
Indriya. Because we are being deviated from our eternal relationship with God, Kṛṣṇa, on account of our too much being engaged in sense gratification. Bhogaiśvarya-prasaktānāṁ tayāpahṛta-cetasām (BG 2.44). Lord says, Kṛṣṇa says, "Those who are too much after bhoga and aiśvarya, material enjoyment and material opulence," prasaktānāṁ tayāpahṛta-cetasām, "whose heart has been taken away by the process of sense gratification, for them, it is very difficult to be situated in samādhi." Bhogaiśvarya-prasaktānāṁ tayāpahṛta-cetasām.