Key to an understanding of the final scene of "A Good Man Is Hard to Find" is the Misfit's remark about the grandmother:
"She would have been a good woman,...if it had been somebody there to shoot her every minute of her life."
For, O'Connor's story is one of her anti-parables in which the face of death is enlightening and grace is devastating to the one receiving it. The violence of the Misfit startles the grandmother out of her pretensions of social superiority and forces her to recognize that she, like the Misfit, is a sinner. She, then, makes this religious connection with the Misfit, and, in so doing, becomes the recipient of grace.
In Mystery and Manners, O'Connor declared that her "subject in fiction is the action of grace in territory held largely by the devil." The Misfit is, ironically then, the agent of grace for the grandmother. For, the violence of the evil Misfit, the brutal deaths of her family, is what shakes the grandmother from her complacency to enter into faith.