Why Tremble? Sayings In Which Luther Found Comfort

Luther, 1530:

Christ himself says, John 16, 'Be of good cheer; I have overcome the world.'

This cannot be wrong--I'm sure of it--that Christ, the Son of God, has overcome the world. Why do we tremble before the world as before a triumphant conqueror? It is worth going to Rome or Jerusalem on one's knees to obtain those words of Christ. 

--'Sayings in Which Luther Found Comfort,' in Luther's Works, Volume 43, Devotional Writings II, 172

Dane Ortlund