Arjuna asks Krishna a series of questions. He first asks what Brahman, the highest self, and action are. Then, he asks how Krishna speaks of the highest being and the highest god, what the highest sacrifice is, and whether the restrained sages know Krishna when they depart to join him. Krishna responds that Brahman is the imperishable, and the highest self is one’s nature, from which “all states of being” emerge. Action is “sending forth,” “finite existence” is the highest being for the embodied, and “the great spirit” is the greatest of the gods. The highest sacrifice is Krishna himself, “here in this body,” and one who remembers him joins his state of being in death.
Again, Arjuna asks Krishna to clarify some of the concepts he has introduced. Krishna answers each of Arjuna’s questions in turn, perhaps creating more mystery than he resolves. Brahman and the highest self are one and the same, and God coming down to earth in the form of Krishna is the highest form of sacrifice because he takes up a material form in order to save Krishna and humanity from their ignorance.
In death, one goes to “whatever state of being / one remembers” in that moment, so by always remembering Krishna, even during battle, Arjuna can join him. By practicing yoga and meditating on the formless “ancient one” who supports everything, one can ensure ascension to “this divine, highest spirit” in death. The path of asceticism, a dispassionate and celibate path on which one only desires knowledge of the infinite, restricts the body, and concentrates on “Om,” leads one on “the highest way.”
Strictly speaking, Krishna does not declare that people must be thinking of him when they die in order to achieve transcendence. However, doing so is clearly a foolproof (if immensely difficult) means to enlightenment, and equivalent to the mindset of sacrifice. People’s reincarnation into what they think about upon death might explain why the wicked (who probably die with wicked thoughts) tend to return to wicked bodies.
One who does not stray should have no trouble joining Krishna instead of being reborn in another body, “that impermanent / place of sorrow.” Souls cycle through rebirths, besides those who find Krishna. Everything with form comes from the formless and dissolves back into it after completing the cycle, which Krishna explains as the coming and going of cosmic days and nights. This formless state of being is “imperishable;” it does not disappear when “all beings are lost,” and no being returns from it. This is the highest state, which incorporates all beings and through which the world is “woven.”
Nothing is created or destroyed because everything is eternal, and Krishna compares birth and death in the universe’s purview to the way people awaken each morning afresh. Extending this analogy, the death of the body is like the eternal self’s reincorporation into Brahman, which makes it an immortal part of God.
People can move along this path either at the height of day with a waxing moon when the sun lies to the north, or in the night with a darkening moon when the sun lies to the south. These paths of light and dark are eternal. By following the way of light, one does not return to the world, but by following the way of dark, one is reborn. But one who properly practices yoga, rather than merely offering sacrifices and gifts, bypasses rebirth and “goes to the ancient / highest place.”
These two paths hearken back to the Vedic Upanishads (part of the Vedas), in which the moonlit path stands for meditation, and the path of the dark moon stands for the blind rehearsal of rituals. Krishna is suggesting that merely performing one’s worldly duties is insufficient unless one does so with the proper knowledge and detachment from action.