All that is initially evil does not arise from another domain that could endure against Him. Now that we understand that what He does must ultimately be good, we must understand another truth. This is that there is certainly only one domain, contrary to the claim of the unbelievers that there are two domains. When we say that our God is one, it is necessary to understand two things.
The first is that even though we see such a multitude of diverse phenomena in the universe and so many different and opposing causal chains, we know that even so, there is only One God, blessed be His Name, and only one Will. The second thing that follows from saying that God is one is that no other will can limit Him, even one brought into being by Him. And it is certainly impossible that two powers or realms exist, one creating good and the other creating evil. “HaShem our God, HaShem is One” – with every kind of oneness and unity.