Speaking in trance is a mediumistic process. It only works in the presence of a medium who has mastered this form of spiritism. The medium goes into a trance, a kind of deep sleep, and the spirits are then said to be able to speak to the people present through the medium.
Dr Kurt Koch writes in his book “Occult ABC”:
Ex. 218 I had been asked to preach at a Lutheran church in South Africa. The last minister had been led astray by spiritists. When he hesitated, the spiritists told him that Luther spoke at their meetings. What Lutheran pastor would not be eager to hear Martin Luther speak? So the Lutheran pastor went to the séance with his wife and daughter. The pastor quickly realised that what was going on was a shameless deception on the part of the demons: Martin Luther had certainly never preached in such a primitive and unspiritual way as through this spiritistic medium. After a terrible struggle, he renounced Spiritism. But he died a short time later. His wife and daughter were unable to free themselves and remained trapped in the spiritists‘ coils.
An example from „Christian Counseling and Occultism“ by Dr. Kurt E. Koch: A bicycle shop was broken into and a large number of bicycle accessories were stolen. The victim reported the theft to the police. He also asked the leader of a spiritist circle to hold a séance in the shop in question so that a speaking medium could describe the perpetrator with the help of the „spirits“. The séance took place in the presence of six people. The medium described the perpetrator, thus arousing strong suspicions of a worker in debt. This séance did not lead to the complete discovery of the culprit, as two relatives of the suspect were present.
Quite apart from the dubious and highly questionable nature of such a search service, this meeting had a curious pastoral aftermath. Two Christians involved in the meeting, a man and a woman, came to a counselling session complaining of melancholy, weariness of life and the observation of haunting phenomena.