|St. John of the Cross on visions and visionaries
This is what St. John of the Cross, the acknowledged spiritual master in these matters, has to say about the dangers which visionaries are open to in his Dark Night of the Soul (2.2:3). Although he is essentially talking about "imaginative" visions, these points also broadly apply to "exterior" visions.
"... the devil causes many to believe in vain visions and false prophecies; and strives to make them presume that God and the saints are speaking with them; and they often trust their own fancy. And the devil is also accustomed, in this state, to fill them with presumption and pride, so that they become attracted by vanity and arrogance, and allow themselves to be seen engaging in outward acts which appear holy, such as raptures and other manifestations. Thus they become bold with God, and lose holy fear, which is the key and the custodian of all the
virtues; and in some of these souls so many are the falsehoods and deceits which tend to multiply, and so inveterate do they grow, that it is very doubtful if such souls will return to the pure road of virtue and true spirituality."
Speaking of visions in general, and in particular of the danger of desiring them, he writes in The Ascent of Mount Carmel (2.11:8,12):
8. "It is always well, then, that the soul should reject these things, and close its eyes to them, whencesoever they come. For, unless it does so, it will prepare the way for those things that come from the devil, and will give him such influence that, not only will his visions come in place of God's, but his visions will begin to increase, and those of God to cease, in such
manner that the devil will have all the power and God will have none. So it has happened to many incautious and ignorant souls, who rely on these things to such an extent that many of them have found it hard to return to God in purity of faith; and many have been unable to return, so securely has the devil rooted himself in them; for which reason it is well to resist and
reject them all. For, by the rejection of evil visions, the errors of the devil are avoided, and by the rejection of good visions no hindrance is offered to faith and the spirit harvests the fruit of them."
12. "It is clear, then, that these sensual apprehensions and visions cannot be a means to union, since they bear no proportion to God; and this was one of the reasons why Christ desired that the Magdalene and Saint Thomas should not touch Him. And so the devil rejoices greatly when a soul desires to receive revelations, and when he sees it inclined to them, for he has then a great occasion and opportunity to insinuate errors and, in so far as he is able, to derogate from faith; for, as I have said, he renders the soul that desires them very gross, and at times even leads it into many temptations and unseemly ways."
St. Teresa of Avila
St. Teresa of Avila makes these comments about those with a tendency to believe that they have received revelations:
"Not three or four only, but a large number of people have spoken to me on the subject, and therefore I know by experience that there are souls which, either because they possess vivid imaginations or active minds, are so wrapped up in their own ideas as to feel certain that they see whatever their fancy imagines. If they had ever beheld a genuine vision, they would recognise the deception at once. They themselves fabricate, piece by piece, what they fancy they see: - no after effects are produced on the mind, which is left less moved to devotion than by the sight of a sacred picture (Interior Castle, Sixth Mansion, ch. ix, 6).