God overpowers all

St. John of Kronstadt

There is nothing impossible unto those who believe; lively and unshaken faith can accomplish great miracles in the twinkling of an eye. Besides, even without our sincere and firm faith, miracles are accomplished, such as the miracles of the sacraments; for God's Mystery is always accomplished, even though we were ... incredulous or unbelieving at the time of its celebration. "Shall their unbelief make the faith of God without effect?" (Rom. 3:3). Our wickedness shall not overpower the unspeakable goodness and mercy of God; our dullness shall not overpower God's wisdom, nor our infirmity God's omnipotence.

[My Life in Christ]

Demons appear as angels of light

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 3 ~ On Exile

¶29. Demons often transform themselves into angels of light and take the form of martyrs, and make it appear to us during sleep that we are in communication with them. Then, when we wake up, they plunge us into unholy joy and conceit. But you can detect their deceit by this very fact. For angels reveal torments, judgments and separations; and when we wake up we find that we are trembling and sad. As soon as we begin to believe the demons in dreams, then they make sport of us when we are awake too. He who believes in dreams is completely inexperienced. But he who distrusts all dreams is a wise man. Only believe dreams that warn you of torments and judgments. But if despair afflicts you, then such dreams are also from demons.
This is the third step, which is equal in number to the Trinity. He who has reached it, let him not look to the right hand nor to the left.

Demons know nothing about the future from foreknowledge

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 3 ~ On Exile

¶28. The demons of vainglory prophesy in dreams. Being un­scrupulous, they guess the future and foretell it to us. When these visions come true, we are amazed; and we are elated with the thought that we are already near to the gift of foreknowledge. A demon is often a prophet to those who believe him, but he is always a liar to those who despise him. Being a spirit, he sees what is happening in this lower air, and noticing that someone is dying, he foretells it through dreams to the more light-minded. But the demons know nothing about the future from foreknowledge. For if they did, then the fortunetellers would also be able to foretell our death.

A phantasy is an illusion

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 3 ~ On Exile

¶26. A dream is a movement of the mind while the body is at rest. A phantasy is an illusion of the eyes when the intellect is asleep. A phantasy is an ecstasy of the mind when the body is awake. A phantasy is a vision of something which does not exist in reality.

Evil conversation corrupteth good habits

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 3 ~ On Exile

¶24. By much labour and effort a good and stable character is developed in us. But what is achieved with great labour can be lost in a single moment, for 'Evil conversation corrupteth good habits,' being at once worldly and disorderly. The man who associates with people of the world or approaches them after his renunciation will certainly either fall into their traps or will defile his heart by thinking about them; or if he is not defiled himself, yet by condemning those who are defiled, he himself will be defiled.

Think of Him Who for our sake was exiled from Heaven to earth

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 3 ~ On Exile

¶22. When men or demons praise us for our exile, as for some great exploit or achievement, then let us think of Him Who for our sake was exiled from Heaven to earth, and we shall find that throughout all eternity it is impossible for us to make return for this.

Abraham the greatest exile

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 3 ~ On Exile

¶20. No one has surrendered himself to exile to such an extent as that great man who heard: 'Go forth out of thy land, and out of thy kindred, and out of the house of thy father.' And then he was called into a barbarous land that spake another tongue.
¶21. Sometimes the Lord has brought more glory to the man who has separated after the manner of this great patriarch, but even if glory is God-given, yet it is excellent to divert it from oneself with the shield of humility.