Why do bad things happen in this world? This question has no easy answer, but I found something that helped me understand a little better. See Romans 9:22-25.
What if God, wanting to show his wrath and make his power known . . . (God is angry at evil and has the power to do something -and he wants to !)
He endures with much long-suffering (He doesn’t get rid of evil and endures it, meaning he is really, really patient with evil and has not stomped it out yet)
The objects of his wrath prepared for destruction (God knows who deserves his anger and has planned for their eventual destruction)
So that (here’s the reason he puts up with evil)
He might make known the riches of his glory to the objects of his mercy . (Why is God so patient? God has a reason for being patient with evil and it is to show his glory to those who need to see His mercy)
whom he had prepared in advance for glory (He already knows ahead of time those who will believe, and he is patient with evil so that more people may see his glory. God is waiting so that others may come to know about Him.)
This is my interpretation of the Romans passage. God WILL destroy evil – whenever He decides it is the right time.