fall on one's sword

Meanings

1. To resign from a job or other position of responsibility, especially when pressured to do so.
2. To voluntarily take the blame for a situation.
3. Used other than figuratively or idiomatically: To commit suicide by allowing one’s body to drop onto the point of one's sword.

Etymology

Refers to the practice of some Roman military leaders, who would commit suicide following a devastating defeat by literally falling on the point of their own swords.