The story of Reverend Curtis Hartman, one of the most powerful characters in the book, is built of irony piled upon irony. Of course, all irony is based on contrast, whether it be between what is said and what is meant, what seems to be true and what is really true, or what one expects to happen and what is meant, and so on.
The most obvious ironic contrast in "The Strength of God" is between appearance and reality. For example, Curtis Hartman, the forty-year-old pastor of the elite Winesburg Presbyterian Church, seems to be a refined scholar. He and his wife are respected by the community where they have lived for ten years; they are apparently happy and above reproach. Yet Curtis Hartman, a respected pillar of society, turns out to be a peeping tom. On the other hand, Kate Swift, the woman he watched, seems to the minister to be what her name implies, a fast or sinful woman. The schoolteacher, however, is really a good person and a conscientious teacher. Strangely enough, after his first sight of Kate Swift and his resulting sexual desires, the minister preaches an unusually powerful sermon. As in "Godliness," appearance is quite unlike reality and results are quite different from expectations.
Another irony lies in Reverend Hartman's name, which certainly suggests heart-man. But at the end of the story we discover that Curtis Hartman refuses to be ruled by his heart. The attraction which the parson feels for the attractive, thirty-year-old Kate Swift probably seemed to Sherwood Anderson a perfectly normal desire, for Anderson believed that man should fulfill himself through love. After the parson watches the teacher lying in bed, he begins to realize how inhibited he and his wife are and decides, "Man has a right to expect living passion and beauty in a woman. He has no right to forget that he is an animal . . . I will throw off the woman of my bosom and seek other women. I will besiege this school teacher. I will fly in the face of all men and if I am a creature of carnal lusts I will live then for my lusts." However, social mores usually thwart man's natural desires and Hartman later interprets his longing for Kate Swift as a sin, a sin he ultimately renounces. The heart thus yields to the dictates of the head.
A stained glass window plays an important part in this fascinating conflict between heart and head. Reverend Hartman first sees into Kate's bedroom through the open window of his belfry-study, where he is working on a sermon. Ironically, in this spot where the minister seems safest from the world's sins, he is tempted. Later in the fall, when the weather is colder, the study window is closed. Made of leaded glass, it depicts Christ laying his hand upon the head of a boy who is looking with rapture into Christ's face. When the minister breaks out a little piece of the window so he can continue to look into Kate's room, the piece of glass broken out just nips off the bare heel of the boy. The allusion is probably to Achilles, who was dipped by his mother in the River Styx to make him invulnerable, but since she was holding him by his heel, that part of his body was not immersed; Achilles was eventually killed by an arrow in his heel. Anderson thus seems to be symbolizing the minister's weakness by having the heel of the worshipper broken off.
Finally, Reverend Hartman has his "vision" and breaks out the whole window. This incident, too, is full of irony. On this particular night, the minister watches as Kate, instead of reading, throws herself naked on the bed and beats the pillow with her fists. She then rises, still weeping, and begins to pray, looking in the lamplight like the boy in the presence of Christ on the leaded window. With a cry, the minister smashes the window through which he is peeking, rushes to the Winesburg Eagle office and there tells the bewildered George Willard: "God has appeared to me in the person of Kate Swift, the school teacher, kneeling naked on a bed . . . she is an instrument of God, bearing the message of truth."
The irony here, of course, lies in the minister's interpretation of what he has seen, for we learn in the next story ("The Teacher") that Kate is weeping and praying not because she has the message of truth for the minister but because she is a desperately unhappy, frustrated woman. She has tried to communicate her "message" to George but she failed. That message had to do with living fully and learning to see "what people are thinking about, not what they say." In smashing his bell-tower window, the minister stepped back into his stultifying, conventional life; he destroyed his chance of learning about a different life and about what other people are thinking; and he has cut his hand, Anderson's symbol of communication. Curtis Hartman is a grotesque who seized upon a truth (man's need for help as evidenced by Kate's prayer) and twisted it into a denial of normal human emotions and he destroyed a possible perception of what people really think and feel. Ironically, because of his "vision," the minister will return to his superficial, conventional life.