There is a clear dichotomy between what is of God (good) and what isn’t (evil)–there are no gray areas (which I’ll post about later).
BUT, unlike ‘natural world’ dichotomies, good cannot be defined by its absence of evil–it just IS (just as God Himself is, was, and will be!).
You see, God exists as the pure paradigm of good, regardless of whether evil does or doesn’t exist. And evil exists because, in being purely good, God allows for free will. From the point He began to create, both in the heavens (angels) and on the earth (humans), His creations had (and have) the freedom to become any kind of vessel.