We are impelled to examine the basis of goodness, greatness and light. Wherever it is fit that infinite greatness and goodness be revealed. But there are also places where diminution is fitting. Then everything rises and returns to a state of total goodness, which doesn't require any measure of withholding. One aspect is like the soul and the other like the body.
Darkness perfects goodness, which is light.
There is no day without night. Day and night provide the basis for the perfection of the framework of time. If not for the darkness, which presents the viewpoint of separation, there would be no drive toward continuous ascent. That drive is basic. If not for the viewpoint of separation, we would only be aware of the quality of completeness.