In John Steinback’s Grapes of Wrath the biblical motif is used in the form of Jim Casy, a preacher Tom remembers from childhood. Casy explains that he is no longer a preacher, having lost his calling. He still believes in the Holy Spirit, but not necessarily the spirituality mandated by organized religion. For Casy, the Holy Spirit is love. Not just the love of God or Jesus, but the love of all humans.
Steinbeck makes a serious inquiry into the eternal problems of humankind--the nature of the divine, the individual's relationship with that divinity, and the results that follow from them. He examines various concepts of God and finds them all wanting, in one respect or another, and finally decides that the most valid concept of the divine is one that closely approximates the Emersonian ideal of the Oversoul. This concept is not stated explicitly, because Steinbeck is writing a novel and not a metaphysical tract. Steinbeck finds religious institutions harmful, an anthropomorphic god unsatisfactory, evangelism evil, and pantheism leaving something to be desired.
Steinbeck uses the grapes as symbols of plenty. The grapes correspond to the cluster of grapes which Joshua and Oshea bring back from their first trip into the rich land of Canaan. Grampa alludes to this meaning of the grapes when he says that he is going to sit in a tub full of grapes in California. Steinbeck's title also corresponds to Julia Ward Howe's song "The Battle Hymn of the Republic" (1862) from which Steinbeck took his title. In his novel, however, the grapes symbolize both plenty and renewal, and bitterness and wrath. The latter meaning alludes to Revelation XIV which states that those who "worship the beast and his image" will "drink of the wine of the wrath of God." It further says.....
