Answer: HaVaYaH is the system of all parts of the universe (Ha-Va-Ya-H) connected into one formula of interaction of the Light with the desire.
There are only two components in the creation—Light and desire. When Light enters desire, forms it for itself and the desire is ready to be like the Light, then such a system of interrelation is called HaVaYaH.
It is immutable, because it is initially defined based on the opposite qualities of Light and desire, which begin to complement each other by becoming mutually imbued with each other.
HaVaYaH is the structure of a corrected desire that has entered into complete adhesion with the Light. And every part of it is also a small HaVaYaH.
HaVaYaH does not change because the quality of bestowal and the quality of reception are initially given, constant, mutually complementary, and it is impossible to change anything here.
From the Kabbalah Lesson in Russian 11/23/17