The Grown-Ups Must Die

After the Israelites rebel and refuse to enter the promised land, "God is furious, as usual, and ready once again to destroy the people, but Moses intercedes and He settles for the forty years. The term is chosen for a purpose: so that all those Israelites who were twenty years old or older at the time of the "going out" from Egypt will die natural deaths in the wilderness... Lincoln Steffens takes this to be the chief political lesson of the Exodus: 'The grown-ups must die.'"

(from Exodus and Revolution, by Michael Walzer, 67)