Elder Ephraim of Arizona on the remembrance of God, and on good thoughts

St. Isidore of Pelusium, in prayer and contemplation of God (source)

  
Elder Ephraim of Arizona on the remembrance of God, and on good thoughts
It is not so easy for the demons to harm a person who keeps the constant remembrance of God in his soul. They can tempt him, but it is difficult for them to harm him. This is because he does not permit them to trip him up, for he is armed with the weapon of the constant remembrance of God. Whoever has his soul’s eyes open and sees God is not easily harmed by the enemies. The very spiritual men of old did not need spiritual books. They did not have such a great need to read many patristic books, because they constantly meditated upon things about God. Whatever they saw immediately gave them an opportunity to meditate upon something, to discover something unknown. All of creation was a university for them. Wherever they turned their eyes, they saw something to meditate upon—sometimes the providence of God, other times His wisdom; sometimes His judgment, other times His teachings, and so on. With the eyes of their soul they saw invisible things. Meditating upon them filled their hearts with spiritual knowledge.

We people of today—since we do not have the eyes of our soul open—do not have the ability to remain in the spiritual meditation. Even when we do see something, we need religious books to know something about God. The minds of these spiritual men were so strong that they could conceive thoughts and ideas with deep wisdom. Our minds are so weak that they can barely retain anything. The Fathers then were, for the most part, simple people; yet, they acquired full knowledge, because the Holy Spirit helped them understand the Scriptures.
The remembrance of God is an all-powerful weapon, a mighty suit of armor against Satan and the various sins. When the mind ceases to remember God and meditate upon divine things, man is overcome by negligence, indolence, forgetfulness, and then by evil desires!
If you see your mind rushing towards the world, know that your soul lacks divine consolation, which is why it turns to the world for consolation. 
When a person’s soul is warm towards God, he is enlightened and feels compunction, and it is impossible for his mind to incline towards the world at the same time. The soul inclines towards the world when it is not united, in a sense, with God. The mind is an area, a place. If God does not occupy it, then the enemy will occupy it. This place cannot remain empty, having neither God nor evil, sin, temptation, or the activity of Satan. The mind is like a mill that is turning. Whatever is thrown into the funnel, which leads to the millstones below, will come out as flour of that type. If you throw wheat in, you will get wheat flour. If you throw thorns in, you will get thorn flour—a harmful substance. The mill is always turning; the mind of man is always working—like a mill. Do you want to have good results? Put good material into the mill. Do you want to find compunction, tears, joy, peace, etc.? Put good thoughts into the mill of your mind—for example, thoughts about the soul, about the Judgment, the remembrance of death, and so on—and then you will get corresponding spiritual results! But if a person puts sinful thoughts into the mill of his mind, he will definitely have sin as a result. The material that will be given to the mind depends on the intentions of man. And these intentions will be either commended or censured. We should always strive to have salvific thoughts and beneficial images in our mind, so that we do not leave room for Satan to throw in his garbage—sinful thoughts and fantasies!
(source)
  

Through the prayers of our Holy Fathers, Lord Jesus Christ our God, have mercy on us and save us! Amen!