Everything the authors of The Zohar write about is revealed in the ten Sefirot when we see all of reality as one spiritual Partzuf. Then different phenomena are revealed in it. These phenomena must be tied to one system, and thus we advance.
Each time something leaves this system and something enters it, something grows and something stands out, as if it is unstable, and there are different signs of illness revealed in it, evil is revealed. But it isn’t an illness and not evil. It’s the revelation of what needs to be corrected now in order to rise to a higher level. This means that everything that is revealed is always revealed negatively from a higher level. Correct yourself and then rise.
From the 2nd part of the Daily Kabbalah Lesson 1/2/13, The Zohar