theodicy

Atheists commonly object that God doesn't exist because evil exists. A good God wouldn't allow evil, or he wouldn't allow evil to the extent that he does or whatever.

God allows evil to exist. He uses it to work greater works than if evil never existed. There can be no redemption without evil, no grace, mercy, or forgiveness. Men are not brave without evil, nor are they strong, generous, or even kind. That's the easy answer. 

God himself says, "Who are you, O man to even question me?" That's God's answer. 

To the atheist I say, "What do you do about evil? How do you respond?" There is evil in this world that cannot be countered by the courage or kindness of men. There is evil that is yet incomprehensible and even invincible. In this world, in this life, evil often "wins." God wants this so we despair of existence and turn to him for strength and life. But what can the atheist possibly offer to those overwhelmed by this evil? Why would he object to God's existence when only God offers justice? Only God's existence can make this evil right, and not in this temporary world, but in the eternal world. God is the only answer to evil that makes sense. Only God can make all things right. If you do not believe in God, you have no reason to live. This world will overwhelm you. Eventually it will destroy you. You can ignore the evil and pretend it doesn't exist. You can drink or screw your life away, but if you ever decide to consider reality, if you ever decide to honestly see existence for what it is, you'll live your life in despair. You'll live your life without hope. If you refuse to believe in God, you abandon all hope of justice. You abandon all hope of redemption. You abandon all hope.