The movement changed them; the highways, the camps along the road, the fear of hunger and the hunger itself, changed them. The children without dinner changed them, the endless moving changed them. They were migrants. And the hostility changed them, welded them, united them – hostility that made the little towns group and arm as though to repel an invader, squads with pick handles, clerks and storekeepers with shotguns, guarding the world against their own people.
– John Steinbeck
The Grapes of Wrath, Chapter 21. Themes of survival, hunger and the unity of the dispossessed who face the same struggles and hostility are covered here. Once tenant farmers, they are now hungry migrants. Regarded as invaders, townspeople take up arms to exclude them from their communities. But this only serves to weld the migrants into one global family of the dispossessed.