The Perfections of God
“The Scriptures indicate that evil has been permitted by God in order that His justice might be manifested in its punishment and His grace in its forgiveness (Rom. 9:22,23). Thus the existence of evil is a reminder of the fact that the universe is designed not for the production of happiness among rational creatures but for the manifestation of the manifold perfections of God.”
Is he willing to prevent evil, but not able? then he is impotent.
Is he able, but not willing? then he is malevolent.
Is he both able and willing? whence then is evil?