Professor Alexei Osipov. "Search for Truth on the Path of Reason".

Nevertheless, what does all of this show? It shows that even obvious supernatural phenomena do not in and of themselves prove the sanctity of those persons, confessions, or religions through which and where they occur. Similar phenomena can occur according to faith (According to your faith be it unto you [Mt 9:29]), or by the action of another spirit (see 1 Jn 4:1; Acts 16:16-18), insomuch that, if it were possible, they shall deceive the very elect (Mt 24:24). They could also be occurring for reasons that we do not yet know.

Here, for example, is a remarkable thing that happened to a spiritual daughter of the holy ascetic of the twentieth century, Bishop Basil (Preobrazhensky) (†1945):

In the home of one of Bishop Basil’s spiritual daughters, Eudocia, a lampada before the icon began to light up by itself at midnight. "It seems that the Lord is calling me to rise for prayer," she thought, but actually she had her doubts. Should she accept this as something grace-filled, or delusional? She could already feel a sort of flattering spirit within her heart, telling her what a woman of prayer she is, since the Lord Himself lights the lamp for her.

The next night Eudocia invited her friend, Ekaterina Dimitrievna, and the lampada lit itself in her presence as well. Then she invited a third witness to spend the night. The same thing happened in her presence. This finally convinced Eudocia to accept the phenomenon as something grace-filled.…

When the holy hierarch heard about this from her, he said sternly, "No, this phenomenon is not from grace, but from the enemy. And because you accepted it as being from grace, I am giving you a penance: do not receive the Holy Mysteries for one year. The lampada will not light itself again."

Truly, the lampada did not light by itself from that day on.

From this we can understand why the saints always regarded all manner of miracles, visions, dreams, revelations, myrrh-streaming, etc. with such great caution and discerning mistrust. They insistently warn the faithful not to hastily accept all of this as a divine miracle, so that they would not fall into a demonic trap by lightly accepting a lie as truth. They therefore said of various inexplicable phenomena, "Do not blaspheme—do not accept it!"

Skhema-Hegumen Savva (Ostapenko). "The Experience of Formation of the True World View."

Skhema-Hegumen Savva (Ostapenko)

One of my spiritual children, K.N. told me a sad story about him, as a fiend plunged him into pride, and as his Guardian Angel initially helped him to recognize the schemes of the Devil.

At work he held a position of responsibility and communicated with great scientists in line of duty. Once a professor said, "If science had discovered what processes run in that and that, we could do that and that ... It would have been a tremendous energy saving". K.N. answered him: "That what happens there is that ...", and unconsciously, as in a dream, he says, he says and he is horrified to think," Well, I am possessed! Who says in me? And what does he say? Now everyone will know that I am insane ... How the authorities will react to this? They will fire me!"

He was ashamed and afraid for himself, he wanted to stop but he couldn’t. Even so he said: "All this you can test by experiments... see for yourself!" A month later, when his words were confirmed, they glorified and exalted him so that for five years he lived in constant fear for himself.

Bishop Palladius. "The Lausiac History".

Chapter XXVIII.  A virgin who fell

Again, I knew a virgin in Jerusalem who wore sackcloth for six years and shut herself up in a cell, taking none of the things that bestow pleasure. In the end she fell, abandoned (by God) because of her excessive arrogance. She opened the window and admitted the man who waited on her and sinned with him, because she had practised asceticism not with a religious motive and for the love of God, but with human ostentation, which springs from vain-glory and corrupt intention. For, her thoughts being engrossed in condemning others, the guardian of her chastity was absent.

Bishop Palladius. "The Lausiac History".

Chapter XXV.  Valens.

There was a man named Valens, a Palestinian by race, but Corinthian in his character - for St. Paul attributed the vice of presumption to the Corinthians. Having taken to the desert he dwelt with us for a number of years. He reached such a pitch of arrogance that he was deceived by demons. For by deceiving him little by little they induced him to be very proud, supposing that angels met him. 

One day at least, so they told the tale, as he was working in the dark he let drop the needle with which he was stitching the basket. And when he did not find it, the demon made a lamp, and he found the needle. Again, puffed up at this, he waxed proud and in fact was so greatly puffed up that he despised the communion of the mysteries. Now it happened that certain strangers came and brought sweetmeats to the Church for the brethren. 

So the holy Macarius our priest received them and sent a handful or so to each of us in his cell, among the rest also to Valens. When Valens received the bearer he insulted him and struck him and said to him: "Go and tell Macarius, 'I am not worse than you, that you should send me a blessing.' So Macarius, knowing that he was the victim of illusion, went the next day to exhort him and said to him: "Valens, you are the victim of illusions. Stop it." And when he would not listen to his exhortations, he retired. So the demon, convinced that he was completely persuaded by his deception, went away and disguised himself as the Saviour, and came by night in a vision of a thousand angels bearing lamps and a fiery wheel, in which it seemed that the Saviour appeared, and one came in front of the others and said: "Christ has loved you because of your conduct and the freedom of your life, and He has come to see you. So go out of the cell, do nothing else but look at his face from afar, stoop down and worship, and then go to your cell." 

So he went out and saw them in ranks carrying lamps, and antichrist about a stade away, and he fell down and worshipped. Then the next day again he became so mad that he entered into the church and before the assembled brotherhood said: "I have no need of Communion, for I have seen Christ to-day." Then the fathers bound him and put him in irons for a year and so cured him, destroying his pride by their prayers and indifference and calmer mode of life. As it is said, "Diseases are cured by their opposites."

http://www.tertullian.org/fathers/palladius_lausiac_02_text.htm#C25

Saint Gregory of Sinai. "On Commandments and Doctrines, Warnings and Promises; On Thoughts, Passions and Virtues, and Also on Stillness and Prayer: One Hundred and Thirty-Seven Texts". From Philokalia, Vol. 4.

115. Those who say or do anything without humility are like people who build in winter or without bricks and mortar. Very few acquire humility and know it through experience; and those who try to talk about it are like people measuring a bottomless pit. And I who in my blindness have formed a faint image of this great light am rash enough to say this about it: true humility does not consist in speaking humbly, or in looking humble. The humble person does not have to force himself to think humbly, nor does he keep finding fault with himself. Such conduct may provide us with an occasion for humility or constitute its outward form, but humility itself is a grace and a divine gift. The holy fathers teach that there are two kinds of humility: to regard oneself as lower than everyone else, and to ascribe all one's achievement to God. The first is the beginning, the second the consummation.

Those who seek humility should bear in mind the three following things: that they are the worst of sinners, that they are the most despicable of all creatures since their state is an unnatural one, and that they are even more pitiable than the demons, since they are slaves to the demons. You will also profit if you say this to yourself: how do I know what or how many other people's sins are, or whether they are greater than or equal to my own? In our ignorance you and I, my soul, are worse than all men, we are dust and ashes under their feet. How can I not regard myself as more despicable than all other creatures, for they act in accordance with the nature they have been given, while I, owing to my innumerable sins, am in a state contrary to nature. Truly animals are more pure than I, sinner that I am; on account of this I am the lowest of all, since even before my death I have made my bed in hell. Who is not fully aware that the person who sins is worse than the demons, since he is their thrall and their slave, even in this life sharing their murk-mantled prison? If I am mastered by the demons I must be inferior to them.

Therefore my lot will be with them in the abyss of hell, pitiful that I am. You on earth who even before your death dwell in that abyss, how do you dare delude yourself, calling yourself righteous, when through the evil you have done you have defiled yourself and made yourself a sinner and a demon? Woe to your self-deception and your delusion, squalid cur that you are, consigned to fire and darkness for these offences.