" This much must be said, however: the plan has the following feature, and any plan with the object of restoring separated humanity to union with God would have to have this feature: its object is to bring it about that human beings once more love God. And, since love essentially involves free will, love is not something that can be imposed from the outside, by an act of sheer power.

Human beings must choose freely to be reunited with God and to love him, and this is something they are unable to do by their own efforts. They must therefore cooperate with God.

As is the case with many rescue operations, the rescuer and those whom he is rescuing must cooperate. For human beings to cooperate with God in this rescue operation, they must know that they need to be rescued. They must know what it means to be separated from him. And what it means to be separated from God is to live in a world of horrors. If God simply "canceled" all the horrors of this world by an endless series of miracles, he would thereby frustrate his own plan of reconciliation. If he did that, we should be content with our lot and should see no reason to cooperate with him. "

― Peter van Inwagen , The Problem of Evil: The Gifford Lectures Delivered in the University of St. Andrews in 2003