"When the demons see you truly eager to pray, they suggest an imaginary need for various things, and then stir up your remembrance of these things, inciting the intellect to go after them: and when it fails to find them, it becomes very depressed and miserable. And when the intellect is at prayer, the demons keep filling it with the thought of these things, so that it tries to discover more about them and thus loses the fruitfulness of its prayer. Try to make your intellect deaf and dumb during prayer: you will then be able to pray."