From Arcana Coelestia ~ Emanuel Swedenborg
As regards the evils and falsities against which the Lord combated, it is to be known that what He fought against was the infernal spirits who were in the evils and falsities, that is, it was the hells filled with such spirits, which continually infested the human race. The infernals desire nothing else than to destroy everyone; and they perceive no greater pleasure than in torturing others.All spirits in the other life are distinguished in the following manner: those who desire evil against others are infernal or diabolical spirits; but those who desire good to others are good and angelic spirits.
A man can know among which he is, whether among the infernal or among the angelic: if he intends evil to his neighbor, thinks nothing but evil concerning him, and actually does it when he can, and takes delight therein, he is among the infernals, and also becomes infernal in the other life; whereas the man who intends good to his neighbor, and thinks nothing but good respecting him, and actually does it when he can, is among the angelic spirits, and also becomes an angel in the other life. This is the distinctive characteristic. Let everyone examine himself by this, in order to learn what he is.
That a man does no evil when he is unable or afraid to do it, amounts to nothing; or that he does good for the sake of self; for these are external things that are removed in the other life. A man there is such as he thinks and intends. There are many who can speak well from a habit formed in the world; but it is instantly perceived whether the mind or intention agrees therewith; if not, they are rejected among the infernals of their own genus and species.
(Arcana Coelestia 1680