Swedenborg wrote in his letter to Ludwig IX, prince of a state of Germany : "The gift of speaking with angels as I speak with them cannot be transferred from one person to another. It has sometimes happened that a spirit enters in and utters some word to a man, yet it is not allowed to the spirit to speak with the man mouth to mouth; this moreover is extremely dangerous, for the spirit enters into the affection of the man's own love, and man's own love is not concordant with the affection of heavenly love. "
Swedenborg always emphasises human freedom and reason. We must not let go of these. To another questioner who asked if it was possible for others to enter into the kind of spiritual life he enjoyed, he replied: "Be careful! That is the direct road to insanity!" Swedenborg realized that when people tried to discover heavenly things by their own speculation, they are not protected against hellish delusions.
-from an article "Swedenborg and Spiritualism".