This week we're back in Revelation looking at the horror of God's wrath poured out on His enemies in chapters 8-9. Highlighted are the destructive tragedies of history caused by creation gone bad, demonic forces let loose and depraved humans in unrestrained violence. It is all used by God to a good end. Still, there is a greater, ultimate purpose of the presence of evil in our world. John Piper explains it well.