The theme of O. Henry's "A Retrieved Reformation" can be stated in either of two old adages. One is "Crime does not pay." The other is "Honesty is the best policy." O. Henry served several years in a state prison for embezzlement. He met a lot of career criminals and saw that in one way or another their choice of a life of crime was a foolish mistake. In O. Henry's story "After Twenty Years" his character 'Silky' Bob seems superficially successful, but he has been on the run all his life. He has never had a home or family, and his only friend in the world, Jimmy Wells, has him arrested and turned over to the Chicago police. Jimmy Wells, on the other hand, has led an honest life and seems like a happy man, content with his job as a policeman. In "A Retrieved Reformation" Jimmy Valentine spells out O. Henry's theme in a letter he writes to a friend in which he tells him:

Say, Billy, I've quit the old business—a year ago. I've got a nice store. I'm making an honest living, and I'm going to marry the finest girl on earth two weeks from now. It's the only life, Billy—the straight one. I wouldn't touch a dollar of another man's money now for a million.

O. Henry uses the character of Jimmy Valentine to illustrate the truth he learned the hard way: that the qualities that make a successful criminal can also make a successful honest man and that the life of an honest man is better in every respect. Jimmy's reformation is threatened when he is exposed as a professional safecracker in the bank where he saves the little girl locked in the vault. However, Ben Price sees this as proof that Jimmy has really become a man of integrity. The story ends with one of O. Henry's trademark surprises.

“Hello, Ben!” said Jimmy, still with his strange smile. “Got around at last, have you? Well, let's go. I don't know that it makes much difference, now.”

And then Ben Price acted rather strangely.

“Guess you're mistaken, Mr. Spencer,” he said. “Don't believe I recognize you. Your buggy's waiting for you, ain't it?”

Jimmy's "strange smile" is probably ironic. He is thinking that once you have taken the wrong path in life there is no turning back. But the story proves that it is never too late to reform.

The theme of "A Retrieved Reformation" can probably be best expressed with the old adage "Honesty is the best policy." When Jimmy Valentine goes to Elmore, Arkansas, he is only planning to set up a business as a "front" from which he can travel to nearby towns and commit his safecracking jobs. However, he sees Annabel Adams and falls in love with her at first sight.

A young lady crossed the street, passed him at the corner and entered a door over which was the sign “The Elmore Bank.” Jimmy Valentine looked into her eyes, forgot what he was, and became another man. 

She is a pure, innocent small-town girl, and he can't hope to win her love unless he goes straight. So he devotes himself to his shoe business and finds that he can be just as successful as an honest man as he was as a criminal. But the advantages of being honest are that he can have a beautiful wife, a family, a home, a circle of respectable friends, and peace of mind. As a criminal he always has to be looking over his shoulder, so to speak. He can never stay in the same place. He is always more or less on the lam. "A rolling stone gathers no moss." Furthermore, he is finding it harder to stay out of jail and finding it harder to get out of jail once he is in. He can see that he is in danger of building a long rap sheet as a career criminal, which would make him a prime suspect any time a big bank burglary was performed. He has pulled three jobs since being released from prison at the beginning of the story, and already his nemesis Ben Price is on his trail. So Jimmy decides to go straight. He expresses O. Henry's moral for this story in a letter he writes to a pal to whom he plans to give his kit of custom-made safecracking tools.

Say, Billy, I've quit the old business—a year ago. I've got a nice store. I'm making an honest living, and I'm going to marry the finest girl on earth two weeks from now. It's the only life, Billy—the straight one. I wouldn't touch a dollar of another man's money now for a million. 

It might be contended that the moral of the story is something like: The love of a good woman can inspire a man. It is true that Jimmy was inspired to change by Annabel. But he had to find out for himself that he could succeed as an honest businessman and that an honest way of life was far more satisfying in every respect than being a flashy, notorious, lone-wolf criminal. Honesty is the best policy. As he tells Billy in his letter, "It's the only life." It really is.