One of the goals of Apologetics is to deal with the objections that people have regarding the existence of God. For the last several weeks, we have been listing some of these objections and the arguments that address them. Here is how Norm Geisler addresses the issue of God being everything including opposites:
Both Good and Evil, Being and Nonbeing. Nontheists say that, if God is infinite, then he is everything, including opposites. He is both good and evil. He is both perfect and imperfect. He is also both Being and nonbeing. But these are opposites, and God cannot be opposites. Further, the theist cannot admit that God is evil or nonexistent. Therefore, no theistic God exists.
The theist rejects the premise that God is everything; he is only what he is—an absolutely perfect Being. And God is not what he is not—an imperfect being. He is the Creator and not a creature. God is pure and necessary existence. So, he cannot be nonexistent. God cannot be opposite of what he is, any more than a triangle can be a square or a circle can be a rectangle.
When we say that God is unlimited or infinite, we do not mean that he is everything. It does not mean, for example, that God is limited and finite. The unlimited cannot be limited. The uncreated Creator cannot be a created creature. The standard for all good cannot be evil.
Geisler, N. L. (1999). In Baker encyclopedia of Christian apologetics (pp. 292–293). Grand Rapids, MI: Baker Books.