One theme for John Steinbeck's The Pearl, which he terms a parable, is The Evil of Greed, One of the Seven Deadly Sins.
Steinbeck's parable teaches the reader certain things about Greed:
1.When a man is consumed with greed, he can lose sight of what is truly valuable, and he can, then. forfeit that which is valuable.
In his desire to hold on to the pearl and find a buyer so that he can attain wealth, Kino endangers his family, those for whom he lives. No longer does he hear the song of the Family; instead, it is the song of Evil that plays in his head:
The music had gone out of Kino's head, but now, thinly, slowly, the melody of the morning, the music of evil, of the enemy sounded, but it was faint and weak.
After he refuses to be duped by the pearl buyers, strange men pursue Kino and his family and they lost their former peace and contentment.
2.Greed is a corrupt force that invites evil deeds.
In Chapter III, for instance, when word of Kino's having found The Pearl of the World spreads,
...all manner of people grew interested in Kino--people with things to sell and people with favors to ask.
In a way Kino now becomes an enemy as he stands in the way of the townspeople and that which they desire, his potential wealth, and what he can give them. He becomes the target of their envy.
3. Greed blinds people as they fail to realize that what is truly valuable cannot be purchased at any price.
As Kino struggles to hold on to the pearl, his wife Juana begs him to throw it away: "This thing is evil...This pearl is like a sin! It will destroy us...." But, Kino perceives it differently, telling her,
"This is our one chance....Our son must go to school. He must break out of the pot that holds us in."
"It will destroy us all," Juana cried. "Even our son."
Her words are prophetic as the baby is shot when a bullet meant for a coyote kills him. The child for whom Kino originally sought the Pearl of the World is gone. As Juana carries their dead baby through the town, she and Kino go to the water's edge and Kino hurls the pearl into the sea as it is now worthless to them without their son.