“Is not an intellect filled with concern for the good of others (paramartha) the very foundation of Dharma, O Brahmins?”
To think only of one's own happiness, one's own sorrow, one's own life, but to give no thought to the duties one owes to the world — that is selfishness. But true worth cannot be mere selfishness. Even the beast, when it feeds, leaves much behind for other creatures.
Chapter 26 of 35 — 7 parts, 20 min in total.
Dharma is rendered as duty, righteousness, law, or the right way to live, and none of those is quite it. It is closer to the thing that holds a situation together — what a person in this role, at this moment, with these obligations, ought to do.
The Mahabharata's central difficulty is that dharma is not a fixed rulebook. Bhishma's vow is dharma; his silence in the assembly hall is adharma; both come from the same commitment. Yudhishthira is called Dharmaraja and still stakes his wife at dice. The epic keeps refusing to let dharma be simple.
Krishna is the one who repeatedly cuts through — sometimes with counsel, sometimes with actions the characters themselves find questionable. The Gita's closing instruction is not a rule but a release: set aside all other duties and take refuge in what is highest.