The Question and Answer section for The Grapes of Wrath is a great resource to ask questions, find answers, and discuss the novel.
Do you mean a reference in the book? Much of the book was about this.
Here is a quote: "The great owners ignored the three cries of history. The land fell into fewer hands, the number of the dispossessed increased, and every effort of the great owners was directed at repression. The money was spent for arms, for gas...
Native Californians wanted profit.... a living that would give them wealth and luxury. The barbarians (Okies) merely wanted land and food.