3 ideas
Ellerbee, a generous Minneapolis liquor-store owner who treats his employees and customers well, is shot dead in a holdup. At Heaven's gate he learns he is damned anyway, and is consigned to a sweltering, tedious Hell where his killer and others also end up. The case tests any claim that a moral life guarantees a just reckoning, because here conscientious goodness buys nothing against a judge whose criteria are arbitrary.
God finally explains that He made the world as a work of art and runs it by the standards of narrative: suffering, reversal and catastrophe exist because they make a better story. He then destroys everything for the sake of the plot. If the maker's motive is aesthetic, the problem of evil stops being a puzzle, because pain is not an unexplained defect but a deliberate structural choice, like conflict in fiction.
When the final judge rewards and punishes by whim, the killer and his victim can land in the same place. Virtue loses its instrumental value. What remains is either rage at the judge or doing good for its own sake, with no promise of payoff. The comedy comes from characters who keep appealing to fairness in a system that never agreed to be fair.