A primary literary work is the Bible, which appears frequently in this story. Manley is a Bible salesman, which is ironic, obviously. Also, Manley ends up epitomizing evil at the end of the story in many ways. He has deceived Hulga deliberately, taken full advantage of her physically and emotionally, and has stolen her leg, which represents a "spiritual rape."
The Enotes on this story point out that:
As with many of O’Connor’s stories, in “Good Country People” the protagonist achieves the possibility of redemption through an act of violence perpetuated by evil, which in this story is embodied in Manley Pointer. Hulga’s wooden leg makes her grotesque, but more grotesque is what that symbolizes: her soul’s lacking faith. When Manley steals her leg, he contributes to the work of God because doing so provides Hulga with the opportunity to accept grace and spiritually grow from the humiliating position in which Manley leaves her. O’Connor suggests the possibilities offered by the presence of evil in the world when depicting Manley “disappearing down the hole” in the loft and then “struggling successfully over the green speckled lake” as he leaves Hulga “sitting on the straw in the dusty sunlight.” In these images, Manley is both devil and Jesus, and Joy/Hulga is in a liminal space of possibility.