What Does Dimmesdale congregation think of him? why is that ironic?

Mr. Dimmesdale is so overwhelmed with shame and remorse that he has started to become famous for his sermons. His ability as a speaker is enhanced by the fact that he feels far more sinful than many in his audience. He has even tried to tell his congregation about the sin he committed with Hester Prynne, but always in such a way that they think he is being modest. This causes Dimmesdale even more pain, for he believes that he is also lying to his people.