Here's why:
* The Stakes Are High: Brown has been on a journey of doubt, and he's already witnessed a disturbing procession of seemingly virtuous people participating in the devil's ritual.
* The Unforeseen Revelation: The climax is unexpected because Brown, despite his growing unease, still clings to the belief that his wife, Faith, is innocent. Seeing her there, at the ceremony, shatters that belief and plunges him into despair.
* The Transformation: This moment is not only the apex of the story, but also the turning point for Brown's character. He experiences a profound shift in his worldview, losing his innocence and succumbing to disillusionment and cynicism.
While the ending of the story is ambiguous, the encounter with Faith at the ceremony serves as the pivotal event that irrevocably alters Brown's life and defines the story's central theme of the pervasive nature of sin and the potential for doubt to undermine faith.