A quote that expresses Dimmesdale's guilt in "The Scarlet Letter" comes when he stands with Hester and declares "Behold me here, the one sinner of the world!" Next, he opens his robe and reveals the mark on his own chest.
Throughout "The Scarlet Letter," Reverend Arthur Dimmesdale carries a secret, as he is the one who committed adultery with Hester Prynne. While Hester is made to wear a scarlet letter "A" on her chest, Dimmesdale hides his own complicity. In the end, eaten up with guilt, he confesses to the crowd and shows them the mark on his chest. It remains unclear precisely what the mark looks like and whether it was put there by God, by the devil or by Dimmesdale's own hand.