A moment of grace in "Revelation" has to do with the behavior of the young woman who literally and figuratively throws the book at Mrs. Turpin. Throughout the period when the group is waiting for the doctor to see them, Mrs. Turpin makes hateful, judgemental and racist statements. The young woman who went to college in the North finds her racism downright despicable. When she has reached her limit and attacks Mrs. Turpin, it is arguable that the young woman is experiencing a moment of grace. This depends, of course, on the definition of grace as a manifestation of God's presence. The young woman cannot bear to hear one more self-satisfied and condemning word from the lips of Mrs. Turpin. She hits her hard enough to get her attention but not hard enough to kill or seriously injure her or her husband, who makes no effort to contradict the hateful things his wife is saying.

It can be said that the objection that Christ's contemporaries had with him is that he disturbed the social order of Judea. Consequently, he was sentenced to death by Pontius Pilate. A parallel in this story could be that the college girl represents Jesus. She cannot abide Mrs. Turpin's adherence to the racist social order, so she hits her. Through this violent challenge, she seals her fate. She is seen as a social danger and is wrestled to the ground and carried away, not unlike how the Roman guards carried away Christ because he threatened the established social order.

In the beginning of the story, Mrs. Turpin thinks very highly of herself. She even believes she has the right to pass scathing judgment on the other people sitting with her and Claud in a doctor's waiting room. She thanks God that she was born white and not black. She dismisses one woman as white trash, and looks with "pity" on an ugly and unpleasant young woman, Mary Grace. Mrs. Turpin, who simply can not conceive that she could do anything wrong, finally becomes so obnoxious that Mary Grace throws a book at her, then has a fit. As Mary Grace lies on the floor, Mrs. Turpin asks Mary Grace what she has to say, as if waiting for a "revelation" from her. Mary Grace tells her:

Go back to hell where you came from, you old wart hog

This statement leads Mrs. Turpin to a revelation. She goes to look at her nice, clean, respectable hogs that evening and stares at them for a long time, as if thinking. Then she has a vision of people streaming up to heaven. People like she and Claud are at the end of the line:

They were marching behind the others with great dignity, accountable as they had always been for good order and common sense and respectable behavior. They, alone were on key. Yet she could see by their shocked and altered faces even their virtues were being burned away. She lowered hands and gripped the rail of the hog pen, her eyes small but fixed unblinkingly on what lay ahead. In a moment the vision faded but she remained where she was.

When she sees that even what she thinks of as her "virtues" being burned away by God, she realizes that all the things she prides herself on, her dignity, orderliness, common sense, and respectable behavior, are sins in the eyes of God. Mary Grace was right: Mrs. Turpin has not been any better than a wart hog.

Mrs. Turpin's revelation is that her values have been misplaced: God doesn't care if a person is white or black, respectable or not. These are simply outward wrappings that say nothing about the state of a person's soul. God touches Mrs. Turpin by showing her her flaws , which is a classic way God transforms people in Christian theology. Although we do not know what will happen after the time window of the story, perhaps Mrs. Turpin, having been humbled, can adjust her values to become a more loving, compassionate person.

The moment of grace is after Mrs. Turpin has complained to the black women about the girl at the doctor's office, then she goes down to the pigpen and shouts at the hogs.

The problem is that she interprets the college girl in the doctor's waiting room as insulting her, when she was the one insulting everyone around her by the way she was talking about blacks in a very racist way. Up until her moment of grace, she could still frame her world according to her racist ideology. However after that days events and she is alone at the pigpen, she looses it. Her world view falls apart. She screams at the hogs. Then  no one answers. It is only the silence of the night. It is as if finally she is alone with her obscene and racist world view and she has to look at it.