What is a good thesis statement for the nature of sin and grace in "A Good Man Is Hard to Find" that can lead me into a discussion of the...

Thesis Statement: In Flannery O'Connor's "A Good Man Is Hard to Find," violence is a means to redeeming grace.

Miss O'Connor once wrote,

Redemption is meaningless unless there is a cause for it in the actual life we live.

In "A Good Man Is Hard to Find," when the grandmother is confronted with death as she faces the Misfit and hears the report of pistols firing as the other men execute her family, she tries to tell the Misfit that he is really a good man, a superficial assessment of hers used earlier in the story. In this previous incident, she speaks to Red Sammy and he tells her that he let three men charge their gas, but then asks, "Now why did I do that?" She instantly replies, "Because you're a good man," without really knowing what kind of person Red Sammy truly is.

So, it is not until the family car turns over on the dirt road and they are confronted by the Misfit and his companions that the grandmother becomes truly compassionate.

Faced with death in the person of the Misfit, who has no interest in her false compassion—

"I just know you're a good man" she said desperately. "You're not a bit common!"
"Nome [No ma'am], I ain't a good man...."—

the grandmother's shallow emotion has no effect on her salvation. The Misfit's only goal is survival, and the family and the grandmother are threats to this survival since they can identify the three men.

Then, as the Misfit talks about how Jesus threw everything off balance by supposedly dying on the cross for people, the "old lady" mumbles and sinks down into the nearby ditch with her legs twisted beneath her. Ignoring her, the Misfit says he is not certain of this salvation offered by Jesus because he was not there. He says that if he were there, he would know for certain what is right.

...the grandmother's head cleared for an instant. She saw the man's face twisted close to her own as if he were going to cry and she murmured, "Why you're one of my babies. You're one of my own children!"

Now, with real compassion, her sincere words touch the Misfit, who is repelled "as if a snake had bitten him," and he shoots her three times in the chest. Indeed, the grandmother's real compassion has made her a victim of his violence. But with this violence the grandmother has received grace by means of her maternal compassion. She has her moment of redemption:

...the grandmother...half sat and half lay in a puddle of blood with her legs crossed under her like a child's and her face smiling up at the cloudless sky.

The violent catastrophe that the grandmother has experienced becomes a redemptive catastrophe as it affects her conversion and grace, symbolized by her "legs crossed under her" much as Christ's were when taken down from the cross after He, according to Christian belief, redeemed mankind by dying. Her grace, too, comes only at the moment of grisly death.

Miss O'Connor describes this story as well as her other works in this way:

I have found, in short, from reading my own writing, that my subject in fiction is the action of grace in territory held largely by the devil.