What motivates the narrator in The Tell-Tale Heart to kill the old man?

The primary motivation for the narrator in "The Tell-Tale Heart" is rooted in the intense fear and obsession with the old man's eye, which he describes as "vulture-like" and unsettling. This irrational fear drives the narrator to believe that he must eliminate the old man's eye to rid himself of its torment. The fixation on the eye becomes a symbol of the narrator's mental instability and contributes to his ultimate decision to commit murder. Throughout the story, the narrator insists that he loved the old man and denies any feelings of hatred toward him, which further illustrates that the fear of the eye, rather than any personal animosity or desire for material gain, is the catalyst for his actions. This psychological complexity is central to understanding the narrator's motivations and the themes of madness and guilt in Edgar Allan Poe's work.