I have loved this episode since the first time I saw it. It takes a character like Sawyer who has been trying hard to be unlikable, and digs into his background. When Sawyer sees the kid who reminds him of himself, he walks away from a deal.
The letter is a wonderful touch, as it helps us to see how we as people are prone to become what we hate. And why we feel the need to be hated when we do.
The methods Sayid and Jack are willing to use to try to get the asthma medicine from Sawyer explores the issue that Sawyer raised right away – can one behave in a civilized way when in the wild.
The episode doesn’t have much in the way of explicit religious themes and language. But it is all about introspection, morality, redemption, and the need to recognize that the evil we need to defeat is not “out there” but within us. It also reminds us that even the seemingly evil people have a story that we need to understand, and which, when we take the time to do so, can help us lead them back from the darkness that they have enveloped themselves in.