Keep your mind from malicious thoughts of your neighbors, knowing that such thoughts are hurled by diabolical power, to keep your mind from your own sins and from seeking.
Prayer is the mind's dialogue with God, in which words of petition are uttered with the intellect riveted wholly on God. For when the mind unceasingly repeats the name of the Lord and the intellect gives its full attention to the invocation of the divine name, the light of the knowledge of God overshadows the entire soul like a luminous cloud.
One of the Fathers said: just as it is impossible for a man to see his face in troubled water, so too the soul, unless it be cleansed of alien thoughts, cannot pray to God in contemplation.
When the blessed Eulogius saw an angel distributing gifts to the monks who toiled at all-night vigils, to one he gave a gold piece with the image of Our Lord Jesus Christ, to another a silver piece with a cross, to another a copper piece, to another a bronze piece, and to another nothing. The others who had remained in the church, left the church empty-handed. It was revealed to him that the ones who had obtained the gifts are those who toil at vigils and are diligent in prayers, supplications, psalms, chants, and readings. Those who received nothing or who left the church empty-handed are those who are heedless of their salvation, are enslaved to vainglory and the clamors of life, and stand feebly and lazily at vigils and whisper and jest.