In the Zohar portion of Emor, we learn that as God recognized things would appear chaotic to humanity in the physical world, and that we would be unable to deal with, or improve, such chaos ourselves, He created spiritual events such as Rosh Hashanah, Shavuot and Pesach.
Kabbalistically, these are not religious holidays, but rather markers of what is currently taking place in the cosmos; each one of these spiritual events provides us with aspects of the Lightforce of God to help remove the darkness, chaos, and stumbling blocks that prevent the sharing of joy.
From the Zohar portion of Emor, we get the understanding that on Rosh Hashanah not only are we being judged for our actions during this lifetime, but we are also being judged for all of our actions in previous lifetimes, which we have not corrected. How can we possibly come out clean from that?
I will explain, to make it simple, using the analogy of trees. In the spring, trees are blossoming, once again leaves appear, then fruits appear, and then, low and behold, the trees go back into hibernation. Kabbalist Rav Isaac Luria teaches that the Zohar has a phrase for this — Mati velo Mati (Editor's Note: An Aramaic phrase that literally translates as "It’s there; it’s not there.", referring to a paradox), a concept that explains “death for a moment and then complete restoration” — which allows us to get another infusion of the Lightforce of God. According to the Zohar, trees do not go into hibernation; they actually come to a halt and die. However, before death can actually take hold, we see the tree withering. This is also true with humans. We need to see these changes in ourselves; otherwise we could not pay for our negative actions in both this, and past, lifetimes.
The Zohar says this is what happens on Rosh Hashanah; this spiritual event gives us an opportunity to tap into the process of being reborn, without which, most of us could not survive.
It is Mati velo Mati, the Zohar tells us, that contains all the secrets of the universe. This revelation provides us with an openness of immortality, and the idea that immortality could be a reality; the concept of immortality has not yet taken hold in our physical world because we only observe permanent death. When we speak of immortality, we are speaking of restoration—mortality and immortality at the same time. These concepts are difficult to understand; even clinical death is difficult to understand, because once we put a body in the earth we say the person is gone, but they are not gone by any stretch of the imagination. No one dies with what is written on the death certificate.
Rav Shimon teaches through the Zohar that people do not die of heart attacks or any other reason, but rather because there is a force known as the force of death; this force is a very complex system that takes in all the activities of a person’s life and determines when death will be manifested. Therefore, we are not talking about a cure for heart attacks or other things; once the force of death has been removed from our physical world, there will be no heart attacks or cancers. If we did not learn this from the Zohar, we would have missed out on an important opportunity. If it’s not in our consciousness, it cannot succeed. Without our consciousness, nothing can happen.