The writing and compilation of the Bible has had a greater effect on modern literature than anything except, possibly, the creation of written alphabets and the printing press. The Bible's great influence is obvious in many books of the last century. One such book is John Steinbeck's The Grapes of Wrath.

The attitude of the characters in The Grapes of Wrath toward the traditional Christian set of ideals varies greatly from character to character. The Joads, for the most part, don't express their religion strongly. In the beginning, Granma demands that Jim Casy, a former preacher, bless the meal. Her interjections of "amen" and "hallelujah" into Casy's rambling attempt at a grace show that she doesn't even really hear or comprehend what he is saying, but still demands a blessing out of custom, not devotion. Later, when Grampa dies, the Joads feel that it is customary to leave a few words from the Bible buried with Grampa's body; Tom picks a quote that sounds "just blowed full of religion" (p. 183), although he doesn't really understand its meaning; again, he shows an almost blind devotion to his faith in doing something religious simply out of custom. These situations show a passive devotion to a faith that is more of a custom than a religion to them.

Other people through the story show the opposite view on religion. These people are often generalized as Jehovites. They are viewed by the Joads as good people, but still outsiders. At several points, they try to force their faith on the Joads. One such attempt occurs when Granma is ill. A Jehovite claims that Granma is going to die, and declares that a meeting must be held in her tent to pray for Granma. Ma refuses to disturb Granma. She tells the Jehovites that Granma would be all right with a little rest. After a small argument, the Jehovite leaves with a promise to pray for Granma anyway and to "... forgive ya [Ma] for your hard heart." (p. 272). Another religious fanatic later approaches the pregnant Rose of Sharon. She tells Rose about the weekly dances held at the camp. She terrifies Rose of Sharon with a story about a mother who "hug danced" (dancing so that partners are touching) suddenly "skinnied out" and died. Rose of Sharon is terrified and later tells Ma her fear, that she once "hug danced" with Connie, her husband. Ma makes a point to talk to the woman that scared Rose of Sharon, and ends up warding her off with a stick and having her carried off by a group of men. Some, like the Jehovites and the woman at the camp, turned to faith to survive their hard times. The Joads do not look down upon this, but look at it as odd and foreign. "She's [the woman at the camp] a good woman, but she makes people unhappy." (p. 399).

Jim Casy serves an important role in the religious side of the story. Jim Casy is a former preacher turned wanderer by his questions contradictory to the scripture. Upon returning, he has developed a new, Emersonian perspective on the world, where everyone is a part of a collective holy spirit, making life and all that people do holy. This is summarized in his first expressive religious statement in the book, "Why do we got to hang it on God or Jesus? ... maybe its all men an' all women we love; maybe that's the Holy Sperit- the human sperit.... Maybe all men got one big soul ever'body's a part of." (p. 31). His ideas are clear through much of the book. Some agree with and follow his ideas, making him resemble a sort of modern-day Jesus Christ, only following and teaching different ideas. Jim Casy appears constantly as a leader of men sharing his ideas, fighting for the oppressed Okies (similarly to Jesus leading his disciples despite oppression and intimidation by the Romans). Casy is killed while leading a strike to raise wages on a farm; his rebellious attitudes and intent to aid the larger body of people are passed on to Tom Joad, as Jesus' ways and ideals were passed to his disciples, even after his death. Tom Joad shows that he has adopted Casy's ideas later in the book when he is leaving his family and the cotton-picking camp and tells ma "Wherever they's a fight so hungry people can eat, I'll be there. Wherever they's a cop beatin' up a guy, I'll be there. ... An' when our folks eat the stuff they raise an' live in the houses they build- why, I'll be there." (p. 537). Casy shows, again, his faith to mankind when he sacrifices his freedom for Tom's. The allusion to Christ in the Bible continues to Casy's death, where he is killed brutally by a police officer, the officers resembling the overbearing Romans who oppressed Christians and eventually executed Jesus. Tom's statement to Ma that he can still, sometimes, see Jim Casy alludes to the resurrection of Christ.

The Grapes of Wrath is an excellent example of Christianity's effect on modern writing. Many views of religion are shown, from the extreme religion forced on the Joads by the Jehovites to the passive devotion of the Joads themselves. As many people dealt with religion and the hardships faced during the depression differently, this book stands as an accurate depiction of the religious aspect of the depression.