The Grapes of Wrath
Reverend Casy is the spiritual compass of the entire novel. Throughout the novel, as he soaks in the heartbreak in the world around him, he gradually builds and develops his own philosophy. He believes that all humans are connected through a giant collective soul. Eventually, this philosophy leads him to fight and to die for the rights of migrant workers. Casy inspires Tom and shows him what it means to live for a higher purpose.