Tom encounters the turtle from the previous chapter, picks it up, and carries it under his arm in his coat. He intends to give it to his little brother. Seeking shade, Tom finds Jim Casy, a former revival preacher, sitting beneath a tree. Casy recognizes Tom and recalls baptizing him when Tom was a boy, "too busy pullin' little girls' pigtails." Casy has given up preaching because he is troubled what he calls "a lot of sinful idears-but they seem kinda sensible." He confesses his fear that he used to be a hypocrite; he would excite girls at revival meetings, then lay with them in the grass "ever' time." He worries about how he would treat a "holy vessel" like "just a girl." Casy claims, "The sperit's strong in me, on'y it ain't the same. I ain't so sure of a lot of things." He has decided, "There ain't no sin and there ain't no virtue. There's just stuff people do. It's all part of the same thing." He has resolved to love, not Jesus, but "all men an' all women." In a moment of epiphany, Casy realized that "all men got one big soul ever'body's a part of." These emphases-the interconnected nature of life and the meaning of love-will also figure prominently in the novel.
Casy asks Tom how his father, old Tom, is. Tom reveals that he has not communicated with his father for the past four years; "Pa never did write no letters," to his son or to anyone else. Tom tells Casy some details about the murder for which he has finished serving time; the killing occurred when Tom and his opponent got drunk at a dance. Casy accompanies Tom back to his home, suggesting that Tom's father might "kill the fatted calf like for the prodigal in Scripture." Instead, the two men find the Joad home vacant.
The ex-preacher, Jim Casy is the focus of Chapter four. He tells Tom that he left the Church because he had sexual affairs with girls who came to his revival meetings. He realized that he was looking for love in the real world and not for theological ideals. He says, "I don't know nobody named Jesus. I know a bunch of stories, but I only love people."