Saints Barsanuphius the Great and John the Prophet. "Letters".
Letter 414. Question: "If a sinner should acquire certain visions, should that person not believe at all that these are from God?"
Response: When this happens to a sinner, it is clear that it has from the demons, in order to deceive the wretched soul of that person into destruction. Therefore, one should never believe in these, but one should rather cоmе to know one's own sins and weaknesses, in order always to lead a life in fear and trembling.
Letter 415. Question: "So should one also turn away from these visions, even when they appear in the Form of the Master Christ?"
Response: It is especially then that we should turn away from and anathematize their wickedness and deceit even more so. Brother, never be deceived, therefore, by such demonic assurance. For divine visions certainly occur to the saints, but they are always preceded by calm, peace, and joy in their hearts. Indeed, the saints are always aware of the truth and regard themselves as being unworthy [of such visions]. How much more, then, should sinners never believe these visions, when they are aware of their own unworthiness?
Letter 416. Question from the same [brother]: “Master, tell me how it is that the devil dares to display our Master Christ or holy Communion, whether in a vision or in our imagination?” Response by Barsanuphius.
The devil can display neither our Master Christ himself nor holy Communion, but rather he lies and assumes the form of any person and of mere bread. He certainly cannot, however, in any way display the holy cross; for he cannot find a way to present it in some other form. He knows that we understand the true sign and shape [of the cross], and so he does not dare to use this. In this sign, his strength was destroyed, and through it he was dealt a mortal wound.
Nevertheless, since we do not know the Master Christ in flesh, therefore the devil is able to tempt us with his lies in order to persuade us that it is truly [Christ], so that we may be destroyed through believing in his deceit as being the truth. Thus, when you see the sign of the cross in your sleep, know that it is a true sign and that this dream comes from God. Nevertheless, strive hard to acquire discernment from the holy fathers, and do not trust your own thought. May the Lord illumine the eyes of your intellect, brother, in order to escape every deceit of the enemy.
Letter 417. Question: “My thought tells me: ‘If the holy cross appears to you, you will be found unworthy, and so you will feel proud.’ And yet, afterward, it causes me cowardice and fear.” Response.
Do not be concerned about this; for if the holy cross actually appears to you, it will abolish any puffing sense of pride. For wherever God is, there evil is not.
Letter 418. Question: “I have heard that if a dream appears three times, then it is true. Father, is this so?” Response.
This is not true either. Nor should you believe in any such dream. For the one who appears to us once in the form of a lie can also achieve the same thing three times or even many times. Therefore, do not be ridiculed, brother, but pay close attention to yourself.
Letter 419. Question: “There are times when I can see in my heart that evil thoughts are surrounding my mind like beasts, without, however, any of my thoughts being harmed in any way. What does this mean?” Response.
This is deceit from the enemy, concealing within itself a sense of pride in order to persuade you that evil thoughts cannot bring any harm to you, and in order that your heart may be thus elated. You should not, however, be deceived; rather, remember your own weakness and sins. And invoke the holy name of God in order that he may assist you against the enemy.