That a certain moral discipline is necessary in order not to be deceived, even when you are dealing with one who has a true spirit of prophecy, is implied in the words of Ezechiel, cap. xiv.: "For every man of the house of Israel, and every stranger among the proselytes in Israel, if he separate himself from me, and place his idols in his heart, and set the stumbling-block of his iniquity before his face and come to the prophet to inquire of me by him: I the Lord will answer him by myself.... And when the prophet shall err and speak a word, I the Lord have deceived that prophet.... According to the iniquity of him that inquireth, so shall the iniquity of the prophet be."
S. Augustine (De Gen. ad Lit., lib. xii. c. 13, 14) might be warning those spiritualists who place their security in the peacefulness and truthfulness of their communications: "The discernment of spirits is very difficult. When the evil spirit plays the peaceful (quasi tranquillus agit), and, having possessed himself of a man's spirit without harassing his body, says what he is able, enunciates true doctrine, and gives useful information, transfiguring himself into an angel of light, to the end that, when persons have trusted him in what is clearly good, he may afterwards win them to himself. I do not think he can be discerned except by means of that gift of which the apostle saith when speaking of the diverse gifts of God: 'To another discernment of spirits.' It is no great thing to discover him when he has gone so far as to do anything against good morals or the rule of faith, for then he is discovered by many; but by the aforesaid gift, in the very beginning, whilst to many he still appears good, his badness is found out forthwith."
Again (Confess., lib. x. c. 35), he speaks of the danger of seeking supernatural communications: "In the religious life itself, men tempt God when they demand signs and marvels, not for any one's healing, but simply for the sake of the experience. In this vast wood, full of snares and dangers, what have I not had to drive away from my heart! What suggestions and machinations does not the enemy bring to bear upon me, that I may ask for a sign! But I beseech thee that even as all consent thereto is far from me, so it may be ever further and further."
Amort, De Rev. Priv., p. 20, from Gravina, says: "It is often easier to establish the certainty of the deceitfulness of an apparition than of its truthfulness, because bad angels have their own characteristics, which good angels never imitate; on the other hand, the bad often imitate the appearance and manner of the good."
Amort, ibid., p. 104, from S. John of the Cross, says: "All apparitions, visions, revelations, consolations, sweetnesses, sensations, etc., which are received by the external senses, should ever and always be refused by the soul as much as in it lies.... In most cases they are diabolical.... When they are from God, they are sent in order that they may be despised, and that the soul, by means of the victory wherewith it overcomes these pleasures of the senses, divine though they be, may be led to the things of the understanding."
Ibid., p. 115: "When the words in any supposed revelation take the form of a process of reasoning after the application of the soul in contemplation, God, the natural reason, and the devil may all three concur in the same process."
No test of the holiness of a manifestation is considered quite satisfactory save that of a continued increase in virtue, especially in humility, in degrees corresponding to the increase of the favor; for the devil will not consent to be a master of virtue. When S. Teresa had scruples as to the source of her favors, it was thus her director consoled her.
So cautious is Catholic mysticism; whilst spiritualists are not afraid to keep a sort of spirit-ordinary, where
"White spirits and black, red spirits and gray,
Mingle, mingle, mingle; those that mingle may."
I repeat it, spiritualists who think they are communicating with spirits, and take no pains to test their character, as though the hypothesis of a devil were absurd, are inexcusably silly.