Existence of the Devil, 76 His Character, 76 1. He is Powerful, 77 His Power limited, 77 Why he is permitted to exercise Power, 77 2. He has much Knowledge, 78 3. He is Wicked, 78 4. He is Crafty, Deceitful, and Treacherous, 78 5. He is a Liar, 78 6. He is Malicious, 79 The Devices of Satan, 79 He suits his Temptations to our Circumstances, 80 Impulses to be tried by the Word of God, 81 Subtlety of Satan, 82 Temptations from the World, 82 From our own Hearts, 82 The Heart a Castle, 83 We must set a Watch, 83 The Double Watch, 83 Watch _unto_ Prayer, 83 Watch _in_ Prayer, 84 Watch on the Mount, 84 Watch in Despondency, 84 Watch when Cheerful, 84 Watch in Prosperity, 85 Watch in Adversity, 85 Watch over the Tongue, 85 Watch when doing Good, 85 Watch against Besetting Sins, 85 Watch over the Imagination, 85 LETTER VII. _Self-Denial_, 86 Nature and Consequences of Selfishness, 87 The Selfish Principle surrendered, 87 Self-Denial defined and applied, 89 Essential to Christian Character, 89 Christ's Example, 89 A Caution, 90 LETTER VIII. _Public and Social Worship, and Sabbath Employments_, 90