11. Thus said the Lord of Hosts, Harken not unto the words of the prophets that prophesy unto you; they make you vain: they speak a vision of their own heart, and not out of the mouth of the Lord. They say still unto them that despise me, The Lord hath said, Ye shall have peace; and they say unto every one that walketh after the imagination of his own heart, No evil shall come upon you. For who hath stood in the counsel of the Lord, and hath perceived and heard His Word? Who hath marked His Word, and heard it? I have not sent these prophets, yet they ran: I have not spoken to them, yet they prophesied. I have heard what the prophets said, that prophesy lies in My name, saying, I have dreamed, I have dreamed. How long shall this be in the heart of the prophets that prophesy lies? Yes, they are prophets of the deceit of their own heart And when this people, or the prophet, or a priest, shall ask thee, saying, What is the burden of the Lord? Thou shalt then say unto them, what burden? I will even forsake you, saith the Lord (Jeremiah, 23:16-18, 21, 25, 26 & 33).
My friends, I wish to talk to you about this passage from the prophet Jeremiah. Speaking through his mouth, God said: "It is the vision of their own hearts which makes them speak in this manner." These words clearly indicate that already in those times the charlatans and the impassioned abused the gift of prophesy and exploited it. They consequently abused the simple and almost blind faith of the people by predicting, for money, both good and agreeable things. This kind of fraud was very widespread within the Jewish nation, and so it is easy to understand that the poor people, in their ignorance, had no possible means of distinguishing the good from the bad, as they were always more or less duped by the pseudo-prophets, who were nothing more than imposters and fanatics. There is nothing more significant than these words: "I did not send these prophets yet they run, I have not spoken to them yet they prophesy." Further on it says: "I heard these prophets who prophesy lies in My Name, saying, I have dreamed, I have dreamed." This is one of the ways they used to explain the confidences they were supposedly given. The masses, being credulous, did not think to dispute the truth of these dreams and visions. They thought it quite natural and frequently invited these 'prophets' to speak.
After the words of the prophet, listen to the wise counsel of the Apostle John, when he said: "Do not believe in all the Spirits. First test them to see if they come from God." This is because among those who are invisible there are also those who take pleasure in deluding, if they have the chance. The deluded ones are, as we can see, the mediums who do not take the necessary precautions. Beyond all doubt, it is unquestionably one of the greatest stumbling blocks against which many come to grief, especially when they are new to Spiritism. For them it is a test from which they will be able to extricate themselves only by using much prudence. Therefore, before anything else, learn to distinguish the good from the bad Spirits so that you, in your turn, may not become a false prophet. - LUOZ, a Protecting Spirit (Carlsruhe, 1861).