God created the possibility of evil; people actualized that potentiality. The source of evil is not God's power but mankind's freedom. Even an all-powerful God could not have created a world in which people had genuine freedom and yet there was no potentiality for sin, because our freedom includes the possibility of sin within its own meaning.
Peter KreeftThe field of earth and of our human nature is now no longer barren but full of the seed of divine life. But it takes time for the seed to grow, for the Kingdom to come, and we are commanded to pray and work for that coming, that growth, even if we do not yet see the fruits, or even the blossoms, or even the leaves...
Peter Kreeft