Krishna describes the “imperishable” ashvattha tree, whose roots extend into the air and branches burrow underground; its leaves are the Vedas’ sacred knowledge. The branches grow through the gunas, creating sensory objects, and from the roots grow human action. But the tree’s true form and ongoing life cannot be seen here, until “the strong axe / of non-clinging” cuts the roots of action and one can find the ancient spirit from which activity originated and go to the “imperishable place” beyond life and death.
The complex metaphor of the ashvattha tree comes from the Vedic Upanishads; these trees grow boundlessly in every direction, much like the limitless Brahman that has no conceivable beginning, middle, or end. Yet, like the eternal self that is a fragment of Brahman, the tree is rooted in the world and one must learn to uproot it in order to unite with the immateriality of the imperishable divine.
The sun, the moon, and flame do not light up Krishna’s “highest dwelling place.” The eternal selves “in the realm of the living” are a fragment of Krishna that draw in the worldly senses as well as the sixth sense, the mind. When the self enters or departs a body, the senses go with it; this self rules the senses and enjoys their objects, but only the wise can see this, and even many dedicated practitioners of yoga cannot despite their effort.
Krishna’s reference to the light of the world and the serene darkness of eternity recalls the imagery of him scorching the earth, destroying it as he brings it to enlightenment, as well as emphasizing that transcendence should not be conceived through the senses. The self again figures as an outside observer on the world, an awareness privy to the senses but not their seat.
Krishna notes that the sun’s brilliance continually lights up the world, even if from the moon’s reflection or in fire. That brilliance is his own, for he sustains all beings, forming their breath and the “memory, wisdom and reason” in their hearts. He even created and knows the Vedas. There is a destructible spirit in the world—beings—but also the indestructible one that stands above them. And there is a highest spirit, the highest self, that sustains the three worlds, and that is Krishna. The clear-minded recognize and devote themselves to him. He can tell people “this most secret rule,” leading them to become “filled with insight” and achieve wisdom when they awake.
The world’s light is also a dimension of Krishna—the fact that all light and energy on the earth originates in the sun also offers a salient metaphor for Krishna’s ability to sustain the world without taking part in it. The “three worlds” Krishna references are most likely the Vedic worlds of heaven, sky, and earth.