Chapter fifteen opens with an image that reverses an old one. The world is a fig tree, imperishable in tradition, with its roots above and its branches below, its leaves the Vedic hymns; the one who knows it knows the Veda. Its branches spread downward and upward, nourished by the strands, and its buds are the objects of sense; below, its roots stretch out into the world of men, binding by action.
The instruction that follows is unusually violent for this book. The tree's form is not perceived here, the chapter says, nor its end, nor its beginning, nor its foundation; having cut this deeply rooted fig tree with the firm axe of non-attachment, that place should be sought from which those who reach it do not return.
The tree is worth pausing on, because it inverts the shape of a living thing. A tree with its roots in the sky draws its life from somewhere other than the ground it appears to stand on. The world of ordinary experience is depicted as growing downward from a source above it, and the leaves, notably, are the sacred hymns themselves, which places even revealed scripture among the tree's foliage rather than outside the whole arrangement.
What the chapter offers instead of the tree is a location. The sun does not illumine that place, nor the moon, nor fire, and those who reach it do not return. Chapter fifteen is short, twenty verses, and it moves faster than any other part of the Gita from image to instruction to goal, which is one reason it has been used liturgically in ways the longer chapters have not.