I think that Flannery O'Connor's short story "A Good man is Hard to Find" is written partially in order to "convert" people who have not yet fully accepted the Chrisian faith. O'Connor, herself being a strong believer in Christianity, probable thought that writing this story will help make people who aren't really living by the Christian rules to seriously consider doing so. Flannery O'Connor was deeply concerned with the values and the direction of the youth at the time. She believe that Christ was no longer enough of a priority to the people of her generation. "A Good Man is Hard to Find" is representative of Flannery O'Connor's concern for the priorities and values of the 1940s.
An example of this, in "A Good Man is Hard to Find" involves the grandmother's strong, southern heritage. She dresses with the intention that anyone who finds her dead on the road will know she was a lady, and she is always telling stories of southern gentlemen courting her. Then, the Misfit, who she "knows: is of quality, southern blood, shoots her and her family, despite her belief in southern hospitality. Grandma is a woman who believes in God, but it seems that her belief isn't really strong up until her confrontation with the Misfit.
From what I understand, most of her works follow a similar pattern. The main character(s) are in some kind of trouble and at the end they see "the light" of God's ways and have their redemption. Christians have often criticized her works for being immoral but in actuality she uses thes extreme situations and portrayals to express the power of God in a positive light. The immoral character of the Misfit is very skillfully portrayed, as is the 'enlightened' character of Grandma. Most of the characters in "A Good Man is Hard to Find" and, probable her other works, go through some kind of methamorphosis, a change in their views of the world and in their perceptions about life and death.