'Yes', I said, 'for the love of God!' What does Montresor mean by these words in "The Cask of Amontillado"?
This response from Montresor is enigmatic, for sure. We know he is mentally unbalanced, but surely even he does not believe he is murdering Fortunato as a reflection of his love for God! Montresor's response may be his mocking Fortunato, making fun of his fear, and enjoying his victim's terror.
If we want to really make much of what he says, consider some of the religious elements in the story. Montresor has lured Fortunato into the catacombs where persecuted Christians sought refuge and where many of their bones still rested.
Some analysis of the story (http://www.enotes.com/cask-amontillado/themes) points out that Fortunato is chained to the wall standing up, taking on the figure of crucifixion and that Montresor walls him up in a small space, similar to the tomb where the crucified body of Jesus was laid. Is Fortunato's death a profane sacrifice? Does the insane Montresor see himself as exercising godlike power? Perhaps.
Montresor sees his malicious act as a righteous and just one; he feels that the slow and cruel murder in this story is justified due to the victim's perceived misdeed against him. This explains his use of God's name while carrying out his action. This line of thought also points to the irony/symbolism behind Fortunato's name -- he is anything but fortunate, and in this story, he meets his "fortune" through the act in the catacombs. This psychological thriller is probably one of Poe's best known works, as it plays upon human fear and depravity. Claustrophobia is a very real psychological condition, and this story very much exploits that rational fear in the reader.
It is to be noted that Fortunato does not call Montresor by name except at the end when he cries, "For the love of God, Montresor!" Poe's main purpose for writing this line was to show that Fortunato understood what was happening and who was responsible. Montresor specifies that one of the requirements for perfect revenge is that the victim know the identity of the "avenger."
A wrong is unredressed when retribution overtakes its redresser. It is equally unredressed when the avenger fails to make himself felt as such to him who has done the wrong.
Fortunato has been drunk ever since Montresor encountered him on the street, and Montresor has kept him drunk by giving him two bottles of French wine. But once Fortunato is tightly chained to the granite wall, the author wants to fulfill Montresor's specifications for redressing a wrong. Montresor explains:
I had scarcely laid the first tier of the masonry when I discovered that the intoxication of Fortunato had in a great measure worn off. The earliest indication I had of this was a low moaning cry from the depth of the recess. It was not the cry of a drunken man.
This is merely to show the reader that Fortunato understands where he is, what is happening to him, and who is responsible. Perhaps Fortunato even understands why it is happening to him. So the following exchange between victim and captor can be interpreted as intended to show that Montresor has made "himself felt as such to him who has done the wrong," as well as Montresor's expression of complete satisfaction at the success of his revenge.
"Yes," I said, "for the love of God!"
This reply probably means that Fortunato, who is begging for mercy, is well aware of his captor's identity and is saying exactly what Montresor wanted to hear him say. Montresor wanted to hear the proud, scornful man begging him for mercy. Montresor could not be there to observe what happened to his prisoner over the following days and weeks. Evidently Fortunato was in for a long, lingering death. But the action ends with
"Yes," I said, "for the love of God!"
Continued from last pane
One also could point to a cynical reference to the sacramental system of the Episcopal church, which often used fortified wines like sherry and port to come in contact with 'the Body of Christ'. The 'Body' is here corrupted, even down to skeletons and disconnected bones, and Fortunato's resting place is going to be hidden in this 'Body'. For Poe, wine was a sacrament not of resurrection but death, as he struggled against his alcoholism mightily over and over, but without much success. So the 'Love of God' represented by the 'Blood of Christ' is seen as being ultimately for him complete death, as he felt walled up in his own misery.