Dharma is the word that opens and closes the Bhagavad Gita. Chapter 1, Verse 1, situates the dialogue on 'the field of dharma, the field of the Kurus.' Chapter 18, Verse 66, culminates with the invitation to abandon all dharmas and take refuge in Krishna alone. Between these bookends, the Gita conducts one of the most sophisticated meditations on duty ever composed.
Dharma in the Gita is many-layered. There is sva-dharma — one's own duty, arising from one's station and nature — which Krishna insists must not be exchanged for another's, however attractive the trade seems (3.35, 18.47). There is sanatana dharma — the eternal moral order that survives the collapse of any single social form. And there is Krishna's own, deeper dharma, in which the outward act is finally less important than the inward attitude with which it is performed.
The Gita's originality is its refusal to make duty a rigid code. Krishna acknowledges that every action is imperfect ('every undertaking is enveloped by defect as fire by smoke,' 18.48), and he refuses to condemn honest action even when it falls short. What matters is not the perfection of the deed but the purity of the offering. Read in sequence, these verses show how sva-dharma, when performed as sacrifice, ripens into the highest freedom — not from action, but from bondage to it.