In Hawthorne's The Scarlet Letter, which character is the most significant in chapters 19-24?

In Nathaniel Hawthorne's The Scarlet Letter, Arthur Dimmesdale becomes the most important character in the last portion of the book. It is here that he and Hester (with Pearl) find each other walking in the forest. We already know about Hester’s sin and how she has reacted to her punishment of wearing the scarlet letter daily. We already know that Chillingworth has devoted his life and sacrificed his own happiness seeking revenge against Dimmesdale. What’s left for the reader is Dimmesdale—will he finally admit his guilt and confess his sin, and will his confession soothe his tortured soul?

In these chapters it appears at first that Dimmesdale will find happiness after all in his plan to escape Boston with Hester and Pearl. When Pearl exhorts him to sail away with her, he thinks to himself, “But now—since I am irrevocably doomed—wherefore should I not snatch the solace allowed to the condemned culprit before his execution?” In other words, why shouldn’t he allow himself a chance at happiness somewhere else, since I he has no chance of finding it here.

But it becomes evident to him that he cannot do so when he walks back into town in a near fit of blasphemous behavior and thoughts: “At every step he was incited to do some strange, wild, wicked thing or other . . .” In deciding to leave Boston and his guilt behind, he has somehow separated himself from his faith. In the end, he cannot live with this result.

So, instead of leaving with Hester, he writes the most moving and impassioned sermon of his career. This sermon is Dimmesdale’s last moment of glory as a clergyman:

The eloquent voice, on which the sounds of the listening audience had been borne aloft as on the swelling waves of the sea, at length came to a pause . . . Then ensued a murmur and half-hushed tumult, as if the auditors [listeners], released from the high spell that had transported them into the region of another’s mind, were returning into themselves, with all their awe and wonder still heavy on them.

From here, Dimmesdale joins Hester and Pearl beside the scaffold, where the story began, and at last confesses his sin to the townspeople. His confession is immediately followed by his death, which leaves Chillingworth with nothing to live for (since avenging himself upon Dimmesdale was his sole reason for living). Chillingworth bequeaths his riches to Pearl. This enables Hester and Pearl to leave Boston and live abroad for a number of years, until Hester finally decides to return to Boston, without Pearl, whose ultimate fate is hinted at but ultimately unknown.

Everything in the final six chapters of the book revolves around and depends upon Dimmesdale’s development and eventual confession. Without it, Hester and Pearl would have continued to live in a kind of guilty limbo, unable to exist apart from the stigma of Hester’s sin of adultery as a young woman.