The Eternal Tree of Life
1. With roots upward, with branches downward, there is said to be an immutable fig tree (ashvattha) whose leaves are the Vedic verses. He who knows that knows the Vedas.
2. Above and below are spread out its branches, grown through the gunas, with objects of the senses as the shoots; and the roots are spread out below, resulting in the bondage of actions in the human world.
The Bhagavad Gita is a modified version of the Vedas and the Upanishads. The eternal tree of the universe described in these verses is also mentioned in the Katha Upanishad, Mundaka Upanishad, Atharva Veda, and Rig Veda. The phenomenal world is compared to a tree whose roots are in the heavens and whose branches spread upward and downward. One who knows that tree is called learned in Vedic knowledge, for that tree contains all the Vedic verses as its leaves. Its shade gives comfort to tired and weary scholars. The gunas cause the pleasant sense objects to blossom in that tree of the universe. Sound, touch, color, form, taste, and smell form additional roots, which spread extensively all over.
The ashvattha (cosmic tree) is described here as an imperishable tree, although it has been previously stated that this universe is transitory. The universe is a manifestation of one supreme imperishable reality, and that absolute reality is all pervading and exists eternally with all its splendor and glory. It is immutable. Yet this universe is transitory, for all the objects of the external universe constantly change as a result of the three gunas, and the universe itself finally is absorbed into the unmanifest. But after universe returns to its unmanifested form, it eventually comes back again to manifestation exactly as it was before. In this sense it is imperishable. It is sustained by that which is eternal.
5. Free of pride and delusion, having conquered the stain of attachment, permanently dwelling in spiritual knowledge, turned away from desires, liberated from the pairs of opposites named pleasure and pain, the undeluded ones go to that imperishable state.
6. Neither the sun nor the moon nor the fire illuminates that, going to which they do not return. That is My supreme abode.
When the aspirant attains freedom from egotism, pride, delusion, and attachments, he becomes content within. Free from all desires, he attains wisdom and finally the highest state of knowledge, which is imperishable in its nature. That knowledge is profound in itself. The light of the sun, moon, and fire have limitations, but the light of knowledge is the highest of all lights. No light is able to dispel the darkness of ignorance except the light of knowledge. The source of all light is in the depths of Atman-not in the sun, moon, or fire. The latter are just fragments of the Light of lights. The aspirant whose delusion has been completely dispelled by the light of knowledge attains the supreme Brahman. Sri Krishna tells Arjuna that the imperishable Brahman is the final abode of all aspirants.
7. In the world of the living ones, My own eternal particle has become the soul (jiva); it pulls the senses, with mind as the sixth, whose basis is Prakriti.
8. Whichever body this Lord attains and from whichever one He departs, He goes taking the mind and senses along in their repository, like the wind carrying fragrances.
9. Ruling over the senses of hearing and taste and touch and smell, as well as the mind, the soul experiences the objects of the senses.
10. The stupefied ones do not observe Him, whether endowed with gunas, He is departing or staying or experiencing. Only those with the eyes of knowledge truly see.
11. The yogis, endeavoring, see Him dwelling within the Self; the unwise, who have not cultivated the Self, do not see Him even though they endeavor.
Rebirth - The individual soul is a part of the supreme Self. The individual soul lives consecutively in various bodies. As the breeze carries the fragrance of the flowers, so the individual soul when casting off the body carries the samskaras with it. Those samskaras motivate the individual soul to dress up in another garment, another body, and thus rebirth occurs. The individual soul is the enjoyer, and the body is like a garment that is changed when it is no longer useful to that soul. The ignorant are not aware of this, but the aspirant who follows the path of discipline with full efforts and a one-pointed mind and who has no desire for external enjoyments realizes the Truth.
16. There are two conscious principles (purushas) in the world: perishable and imperishable. The perishable one is all the beings, and the absolute one is said to be imperishable.
17. But the highest conscious principle, Purusha, is elucidated as the Supreme Self (Parama-atman), the immutable Sovereign, who has entered and then upholds and nurtures the three worlds.
18. Because I am higher than the perishable and also beyond the imperishable one, therefore both in the world and in the Vedas I am glorified as the highest Self.
These verse use two different terms: kshara (perishable) and akshara (imperishable). In this universe we experience two realities: one is constantly changing, and other never changing. One goes through constant birth, change, death, and destruction; and the other is everlasting with no change at all. In human life there are three units: one unit is made up of the body, breath, senses, and conscious mind; the second consists of the unconscious mind and the individual soul; and the third is the ultimate eternal reality, the supreme Self. The first unit is subject to change and destruction, the second is semi-immortal, and the third is completely immortal. The first and second exist only because of the power of the third, the supreme Self, which is the source of life and light and which nourishes and supports the whole universe. It is supreme Self that is the highest of all. The sages and Vedas call Him the supreme Lord.
The aspirant should understand that the body, senses, breath, and conscious mind are one unit-the gross unit of life. That unit constantly undergoes changes, from birth to death. The second unit is the unconscious mind, which possesses and stores all the impressions and memories within itself and remains attached as a vehicle to the individual self, jiva. When the first unit separates from the second unit after death, the unconscious mind and individual soul continue to exist. When the individual soul becomes detached from its vehicle and realizes the supreme Self, one is free from the rounds of births and deaths and is liberated. When the realization of the supreme Self is accomplished, the individual soul becomes one with the supreme Self. The student should understand and firmly know that the supreme Self resides in the subtle most recesses of the body and that the physical body is only an outer and gross sheath. The journey that one should follow in the course of his life is not a journey in the external world but an internal journey leading from gross to subtle and finally to the subtle most supreme Self.
19. The undeluded one who knows Me this way as the supreme Spirit, he, all-knowing, devotes himself to Me with his entire being, O Descendant of Bharata.
20. I have taught you this secret most science, O Sinless One. A wakening to this, one becomes endowed with wisdom, fulfilled as to all actions, O Descendant of Bharata.
As long as one is deluded by external allurements and dissipated by their various enjoyments, temptations, and attractions, he remains unaware of the beauty, grandeur, glory, and majesty of the supreme Self. But when the aspirant possesses the knowledge of both the external and internal worlds and knows the highest of all, he serves the supreme Self with his full devotion and dedication. The secret knowledge of the path of Self-realization has been imparted to Arjuna and to other aspirants. The key is to search, look and see within. One who sees the supreme Lord in His wholeness and then does his duty attains and accomplishes the purpose life.
Here ends the fifteenth chapter, in which the secret knowledge imparted to those who are on the path of Self-realization is explained.