In the vision above mentioned, Mrs. White saw that the mysterious knocking in Rochester and other places, was the power of Satan, and that such things would be more and more common; and that they would be clothed in a religious garb, to lull the deceived to greater security, and to draw the minds of God’s people, if possible, to those things, and cause them to doubt the teachings of the Holy Spirit. GSAM 282.1
But few, if any, at that time had the faintest idea that Spiritualism would spread over the earth as then predicted, or that it would ever assume to be a religion, with its regularly organized churches and pastors. GSAM 282.2