"One type of watchfulness consists in closely scrutinizing every mental image or provocation; for only by means of a mental image can Satan fabricate an evil thought and insinuate this into the intellect in order to lead it astray. A second type of watchfulness consists in freeing the heart from all thoughts, keeping it profoundly silent and still, and in praying. A third type consists in continually and humbly calling upon the Lord Jesus Christ for help. A fourth type is always to have the thought of death in one's mind. These types of watchfulness, my child, act like doorkeepers and bar entry to evil thoughts."