A promise that outlives the reason it was made for, and the ruin its keeping costs everyone around it.
Where it is argued
The birth of the Kuru princes — A blind heir, a pale one and a renunciant's vow leave the succession contested before any of the cousins can walk.
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.
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
Who embodies it
Bhima — The strongest of the brothers, whose two vows in the assembly hall turn a property dispute into something that can only end in bodies.
Karna — Kunti's first son, given away at birth and raised by a charioteer, who spends his life being told his skill does not outrank his upbringing.
Bhishma — The grand-uncle whose vow of celibacy was meant to secure the succession and instead left it disputed for three generations.
Kunti — Mother of three Pandavas and, before any of them, of the son she set adrift on a river and had to watch her other children fight.
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.