This foundational verse defines the body as the 'field' and the conscious soul as its 'knower,' establishing the central metaphor of Chapter 13. Shankara emphasizes that the field includes everything objectifiable — body, senses, mind, intellect, ego — while the knower is pure, non-objectifiable consciousness. Ramanuja teaches that the body is called kshetra because it is where karmic fruits are cultivated, and the individual soul experiences them while depending upon the Supreme. The Bhakti tradition uses this distinction to liberate devotees from excessive bodily attachment. Madhva insists that both field and knower are genuinely real and distinct — the soul is not an illusion, and the body is not merely appearance. Abhinavagupta, from the Kashmir Shaiva perspective, sees the body-field as a contraction of universal consciousness — the knower is awareness choosing to appear limited, and recognition of this dissolves the boundary. Vallabha teaches that both field and knower are real manifestations of Brahman — the body is a sacred instrument of divine service. Tilak draws the practical lesson that knowing you are the knower, not the field, enables detached action in the world. Vivekananda proclaims this as the teaching of strength: you are the immortal knower, not the perishable body, and this realization gives fearlessness to all.