"Greenleaf" is a short story written by Flannery O'Connor that comments on the importance of faith and the acceptance of value systems different from one’s own. The story is set in the rural South, is populated by "grotesques"—marginal people who are often disabled or distasteful in some way—and is an overtly religious narrative.

Religion plays a central role in this story. O’Connor relies heavily on the audience’s familiarity with the gospels, Roman Catholic imagery, and religious tradition to offer didactic insight into the importance of spiritual life. Christian symbols and imagery abound, and O’Connor uses these ideas to discuss the nature of faith and how one should engage with religious values. 

Interestingly, the story unfolds from Mrs. May’s point of view. A bitter, secular woman disillusioned with religion and uncomfortable with prayer, Mrs. May is the lens for O’Connor’s pious commentary. Her protagonist’s nemesis, the devout Mr. Greenleaf, seems to her a shiftless, white-trash farmhand whom she must control with a firm and unrelenting hand. However, the story's imagery suggests otherwise, indicating that he is more spiritually connected and happier than she is or may ever be. For example, O'Connor likens the bottom part of his face to a "chalice," an object central to the Catholic liturgy, as it is the cup from which the communion wine—the blood of Jesus—is drunk. It is the symbol of being consecrated or made sacred. To an observant reader, though likely not to Mrs. May, O'Connor’s description suggests that Mr. Greenleaf is a sacred figure. Though Mrs. May is blind to this fact, distracted by the values of mundane life, her enemy is her true superior in the eyes of heaven.

O'Connor reinforces the Greenleaf family’s moral and spiritual superiority through a reference to the Sermon on the Mount. Mrs. May likens the Greenleafs to the "lilies of the field," which she uses as a contemptuous reference to what she views as their laziness. Instead, this reference conjures the biblical story of the lilies of the field which are to be emulated by those who work and worry too much. The lilies are beautifully dressed, and God finds them beautiful and worthy of praise, regardless of their labors or lack thereof. O'Connor suggests that if Mrs. May was not blinded by her conventional thoughts about the importance of class and appearance, she might learn from Mr. Greenleaf's spiritual wisdom. However, to her, Jesus is an embarrassment:

She thought the word, Jesus, should be kept inside the church building like other words inside the bedroom. She was a good Christian woman with a large respect for religion, though she did not, of course, believe any of it was true.

When the bull gores Mrs. May, O'Connor describes the act as akin to an embrace. As the horns encircle her, readers realize that the goring alludes to the story of the Prodigal Son. Though Mrs. May has strayed from God, the bull returned her to the flock. Like the father, a symbol of God in the parable of the Prodigal Son, the bull is “overjoyed to find her again” and excited to see his "child" returning home. This moment of spiritual awakening is yet another Christian allusion and employs legible biblical imagery to indicate to readers the importance of religion and faith.

 The description of Mrs. Greenleaf during her religious ecstasies is a paradigmatic example of O'Connor's typical grotesques:

Her face was a patchwork of dirt and tears and her small eyes, the color of two field peas, were red-rimmed and swollen, but her expression was as composed as a bulldog’s. She swayed back and forth on her hands and knees and groaned, “Jesus, Jesus.”

Despite the off-putting imagery of this passage, readers are challenged to rise above their prejudices to see to the heart of Mrs. Greenleaf's faith. Her worship may be distasteful, but she does worship—something Mrs. May never does. O'Connor challenges readers to see the world through spiritual eyes, a challenge she sets to the proud Mrs. May, who is ultimately humbled and returned to the true path of faith.