Don't remember if I posted this or not so here I go again...maybe
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) ...
"... 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 and 12):
8. "... 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 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. John of the Cross
St. John of the Cross
Devotion to the souls in Purgatory contains in itself all the works of mercy, which supernaturalized by a spirit of faith, should merit us Heaven. de Sales