Not good against evil, but duty against duty — every open course breaks an obligation the chooser also owes.
Where it is argued
Draupadi's svayamvara — An archery test won by a supposed dead man in disguise, and a mother's careless word that binds five brothers to one wife.
Krishna's counsel to Arjuna — Arjuna asks to be driven between the two armies, sees his own family waiting on both sides, and puts down his bow.
Abhimanyu inside the wheel — A boy who knows how to break into a formation and not how to break out of it is sent in first, and the gap closes behind him
The game of dice — A king who cannot refuse a challenge plays against a loaded opponent, and stakes his brothers, his wife and himself.
Draupadi in the assembly — Dragged into a full court, the queen puts a question of law to the elders — and every one of them declines to answer it.
The night attack on the sleeping camp — The war has been won and the winners are asleep; three survivors of the losing side walk into their camp in the dark
The yaksha's questions — Four brothers drink before answering and fall beside the lake, and the fifth is asked what a man must be before he may drink
Who embodies it
Krishna — Cousin, envoy and charioteer — the one who shapes the war's course without ever lifting a weapon in it.
Arjuna — The archer the whole war is arranged around, who arrives at its opening unable to lift his bow because of who is standing on the other side.
Yudhishthira — The eldest Pandava, called the king of dharma, who gambles away his brothers, his wife and himself without anyone forcing his hand.
Draupadi — Won in a contest she had no say in, married to five men on a careless word, and the only person in the hall who asks a question of law.
Bhishma — The grand-uncle whose vow of celibacy was meant to secure the succession and instead left it disputed for three generations.
Vidura — The half-brother kept from the throne by his mother's rank, who gives the correct advice at every turn and is overruled at every turn.
Abhimanyu — Arjuna's son, sent to open a formation he had said out loud he could enter and not leave, on the day the war stopped keeping its rules.
Ashvatthama — Drona's son, who outlived the war by one night and used it to walk into the winners' camp and end their line while it slept.