The issue of gratuitous evil is, much to the chagrin of the academic elite, ultimately answered by gratuitous love. Though I have presented what I believe to be a solid argument for the logical problem of evil and the evidential problem of evil, it doesn’t offer a 100% rational answer. The reason is that one doesn’t exist, thus any theodicy must acknowledge that it will ultimately be incomplete unless it includes love at the center of its theodicy.
Though this answer isn’t popular among Christian philosophers, we must never forget that in all our theorizing on why God allowed evil, He answered the question of, “God, why this evil” on a cross. Any theodicy that doesn’t include the cross is inherently doomed to failure, because the cross is God’s answer to evil, so how can it be ignored?
The cross serves as the best answer to the existential problem of evil, for while we may not know why God allowed an evil to occur, we can at least know that Jesus suffered evil just as we do. We can know that God was not content to watch us suffer, but instead partook in our suffering. A people may question the king when he allows his people to starve, but if he himself chooses to starve while handing out food to all others then the critics must turn away in shame. So it is with God.
Ultimately, the question of why God allows specific evils will remain a rational mystery to a certain degree. We are limited to say that God allows specific evils because He won’t violate free will in every instance, but this doesn’t say much about why some evils are allowed while others aren’t. But in order to know why God allows some evils and not others requires us to know the mind of God, which is impossible. Why is it that God will step in and drown the Egyptian army, but won’t stop one ethnic group from attacking another ethnic group? We do not know why, other than God has a purpose in stopping some evil. Hence, why evil occurs will ultimately remain a mystery to us, because we do not know the mind of God.
It is in the mysterious aspect, however, that ties into the existential answer to the problem of evil. That it is a mystery and that God’s purposes are known alone to God shows that we should rely on Him even more. To believe in mystery requires us to trust in God. To believe in mystery requires us to rely on Him, which only increases our love for Him.