Have You Lost Your Mind?

Spiritual Warfare - Lesson 9 - Have You Lost Your Mind? - Ephesians 4:17-19. The lost, we are told by Paul, walk in the futility of their mind, having their understanding darkened, being alienated from the life of God, because of the ignorance that is in them, because of the blindness of their heart; who, being past feeling, have given themselves over to lewdness, to work all uncleanness with greediness. What does he mean exactly? And how should that affect our preaching of the gospel?