In order to refute this claim, God willed and created evil, as it is written, “making peace and creating evil” (Isaiah 45:7). In this way, the opposite is immediately manifest, and then it is possible to understand the side of good. Moreover, we will also know that even this evil was not an independent domain in its own right. Only the omnipotent God, blessed be His Name, has the power to bring about what appears to be His very opposite. And through this we will see His great perfection.
Evil is not an independent domain God forbid. It is created by God in order for His creatures to see what is the opposite of good, so that they will not think that there is some other opposite. For the only opposite is that which is actually the opposite. And when they have seen the opposite, and have also seen that it is nothing but His creation, they will have clear knowledge of His perfection and oneness. Then the folly of the wicked and the unbelievers will be exposed. For in the created realms, it is indeed the case that one side can only be known through its opposite. But the way of the Creator is not the way of His creatures at all. For a creature cannot make the opposite of himself. But He made His opposite, and then He negates it – and His oneness is revealed to perfection!