Prior to the fire, the narrator hung his cat from a tree in his yard,
hung it with the tears streaming from [his] eyes, and with the bitterest remorse in his heart;—hung it because [he] knew that it had loved [him], and because [he] felt it had given [him] no reason of offence;—hung it because [he] knew that in doing so [he] was committing a sin—a deadly sin that would so jeopardize [his] immortal soul as to place it—if such a thing were possible—even beyond the reach of the infinite mercy of the Most Merciful and Most Terrible God.
He knows that he is committing a terrible sin, that one could hardly do anything worse (he even regrets it as he does it!), and that it damages his soul in the most hideous and revolting ways. On the very same night, he house catches fire, and he, his wife, and his servant barely escape. His entire wealth is destroyed. In a sense, then, he gets a taste of Hell: it seems that he is punished greatly for his sin of viciously killing the poor cat. Fire can also be cleansing, though, as though it gives the narrator the opportunity to start afresh and do better. After all, he doesn't die; he gets a second chance at life. He does admit that he "regret[s] the loss of the animal," and he begins to "look about" for another such cat to replace the one he killed. However, he ruins this chance, too, growing more and more averse to the new cat he brings home and even beginning to dread it. He tries to kill the new cat, and when his wife prevents him, he kills her instead. The narrator gets a taste of Hell when he is punished by the fire, but rather than take the opportunity to better himself and avoid the real Hell, the narrator grows worse and murders his own wife.