Tom Joad and Jim Casey at the beginning of the novel are two radically different characters, but throughout the book they become more and more similar. It's pretty ironic that an ex-murder and an ex-preacher end up being best friends and also develop and almost brother like bond through out the novel.

Jim Casey is a former preacher turned philosopher. He develops this new philosophy throughout the book. The depression and adultery he has committed has caused him to no longer feel Christian faith and that it is not very relevant to the troubles of the common man. He believes "There ain't no sin and there ain't no virtue. There is just stuff people do." (Chapter 4, pg. 28) Although he does not believe in the Christian faith anymore, in a way I feel that he symbolizes Jesus Christ, because he went to prison for something he didn't do, so...