DELUGE, n. A notable first experiment in baptism which washed away the sins (and sinners) of the world.

Ambrose Bierce (1842–1914?) American writer and journalist

“Deluge,” The Cynic’s Word Book (1906)
    (Source)

Included in The Devil's Dictionary (1911). Originally published in the "Devil's Dictionary" column in the San Francisco Wasp (1882-01-20).

The original Wasp entry included a second sentence: "Since then it has been deemed advisable to let the sinners remain on their good behavior."