Some people have taken with them from the world the idea that we must not talk to devils but avoid them. But I have taught them that talking to a devil is not the least bit dangerous for people whom the Lord protects, even if the whole of hell were to besiege them within and without. This I was able to recognize from such long and miraculous experience that in the end I had no fear. I was not even afraid of talking with the worst members of hell’s crew—an experience granted to me for the sake of learning what they were like.
To those who have wondered at my conversations with devils I have been allowed to add this: Not only does it do me no harm, but devils in the other life were once people. They are the ones who led lives of hatred, revenge, and adultery when they lived in the world. Some of them were even more highly respected than other people at the time. In fact I counted some of them as acquaintances of mine during their physical life. All that “the Devil” means is a mob of such people in hell.
While we are living in the body, we have with us at least two spirits from hell, in addition to two angels from heaven. In bad people, the spirits from hell are in charge, but in good people they are subdued and forced to be useful.
So it is a mistake to believe that any devil has existed from the beginning of creation other than those who once were people of this type.
When the people listening to me hear these things, they are dumbfounded and confess that they had held a completely different opinion of the Devil and the Devil’s crew.
from Secrets of Heaven, Volume 2, Section 968