Why does Roger offer to go to the store in thank you m'am?

In "Thank You, Ma'am" by Langston Hughes, Roger offers to go to the store as a way to express his gratitude toward Mrs. Luella Bates Washington Jones for her kindness after she prevents him from stealing her purse. He feels a sense of remorse and wants to make amends for his earlier actions. This gesture symbolizes his desire for connection and the positive impact of her compassion on his life.