Hawthorne's The Scarlet letter is an interesting and effective study in irony. The glaring message is that while Hester is ostracized and condemned by the Puritain community for her sinfulness and lack of virtue and morality, throughout the work, the reader is meant to feel tht she and Dimmesdale remain the only two characters who in truth embody the virtues of human kindness. In truth, they are the only two characters who truly retain their humanity. Their sin, so abhorred by the community, is what renders them most human, and acts as a sign of their human frailty. The Puritan community meanwhile, though considering themselves to be the height of piety and goodness, is in truth, Hawthorne implies, often cruel and unforgiving. Their rigid adherence to what is literally puritanical, comes at the cost of their humanity and basic human kindness.
It is interesting to note that Hawthorne's grandfather was in fact one of the judges at the famous Salem witch trials. Throughout his life, Hawthorne carried a burdened sense of guilt for the actions of his ancestor. His criticm of the Puritan community emerged partly as a result of this guilt. Hawthorne flips Puritan principles on their head, implying that perhaps, the rigidity of that which is seen as most pure, most righteous, can in truth be the cause of sin and cruelty towards others. Hawthorne's exploration of these issues of morality and its implications, truly make his work progressive.