The Scarlet Letter by Nathaniel Hawthorne

Dimmesdale takes his leave of Hester and Pearl. He tries to focus on the plan: there's a boat docked in Boston harbor that plans to leave in four days, and Hester, who knows the captain because of her charity work, will secure them passage across the Atlantic. Dimmesdale need only have faith in the plan and be strong until they can leave. Unfortunately, he still has duties as the minister, and before he can leave he must deliver the Election Sermon. This does not bother him at first, because he feels invigorated by his meeting with Hester. He walks faster. Breathes easier. Seems full of life.

Dimmesdale thinks he's a changed man. He repudiates his past weakness and cowardice, distancing himself from the man he used to be. When he speaks with the deacon, the minister struggles to hold his tongue and refrain from saying vile, sinful things. When he speaks with an old widow, he cannot remember any lines of scripture and doesn't remember what he whispers in her ear. When he sees a young, beautiful member of his flock in the street, he thinks of shooting her an evil glance and then following it with a snide remark. Instead, he covers his face with his cloak.

When Dimmesdale feels the urge to teach a group of children some curse words, he starts rethinking his plan to leave with Hester. Just then, Mistress Hibbins happens to walk by, wearing a velvet gown and an elaborate headdress. She has heard of his visit to the forest (though not of Hester's plan), and she assumes that he was communing with the Black Man or Devil. She offers to accompany him on his next visit. He refuses, of course, but this only amuses her.

Following his meeting with Mistress Hibbins, Dimmesdale becomes convinced that Hester's plan is actually a deal with the Devil. He rushes home, where he finds a half-written sermon still sitting on his desk. Seeing it, he realizes that he has been tempted by the Devil and come back a changed man, wiser than before. As if on cue, Chillingworth enters the room, asking Dimmesdale about his travels and his health. Surprisingly, the minister refuses the medicines offered by Chillingworth....