Diametrically opposed to the approach of RAMBAM, the understanding of Olam Haba in Kabbalah is far more egalitarian and positive. Although a relatively small percentage of Jews study Kabbalah, but many study RAMBAM, the prevalent understanding of the topic is the Kabbalistic one.Basically, the soul of Man is divided into units which correspond to the limbs and organs of the body. Through the various aspects of the soul, the body can be brought to connect with parallel aspects of the Divine realm. Man can connect to G-d through his soul. This connection is called "devekut" (clinging), and is responsible for true feelings of transcendence and spirituality. In turn, each mitzvah is the vehicle for linking part of the body, through the soul, back into the "root" of the mitzvah above. If one has fulfilled everything they should have, the soul, at the death of the body, ascends to its proper place in Heaven, delighting in the knowledge and closeness with G-d. If something has been blemished, it must be cleansed. It will then descend to Gehinnom, of which there are several levels. This is for the sake of the repair (tikkun) of the soul., not Divine vengeance. Think of it being like surgery. At the conclusion of this cleansing, nearly all souls ascend, with the exception of the most brutally wicked, who must wait for their tikkun, in some cases, until the coming of Mashiach. In many cases, the great Tzaddikim, living and dead, will have pity on these souls, and through their prayers and meditations repair and elevate them. This is done daily during the Tachanun prayer after the morning amidah. Good deeds done in their memory by others will also serve to repair and elevate these people. Upon ascending to Heaven, the soul is constantly rising from plane to plane. coming ever closer to G-d Himself. There is a special elevation on the anniversary of death, known as Yahrtzeit (literally, "the time of the year"). There are various customs performed by relatives and other loved ones on the occasion of the Yahrtzeit. However, if, after cleansing, it is found that the soul is missing an area of fulfillment, something vital left undone, then it is sent back to be born again into this world. It can sometimes happen that a soul already in Paradise, might ascend to a level at which something has been left undone in relation to that level, and will be sent back down to complete the task. Some are sent down not for their own tikkun, but in order to teach and guide others. In some cases, people are reincarnated in non-human for; animal vegetable or mineral. These await being used by a living person in the service of G-d, effecting their final tikkun. Reincanation as a fish is the most common. This is a primary basis for the Kabbalistic understanding of the custom of eating fish at every Shabbat meal. We are elevating souls that still require some tikkun to reach their proper place. In fact, any physical object we use in the service of G-d may have a soul lurking there, awaiting tikkun. There is a constant connection between the living and the dead. IN fact, Rabbi Nachman used the spinning dreidel as a metaphor of physical transforming to spiritual, an vice versa. At the coming of Mashiach, a process will begin in which the world will become increasingly spiritual, until Olam Hazeh (this world) and Olam Haba will come together. Then the resurrection of the dead will come about, as all will on in life.
Rabbi Nachman, speaking in the first decade of the nineteenth century, once foretold: "A great spirit of Atheism and Heresy is descending on the Earth. A simple Jew who washes his hands for HaMotzi (the blessing for bread. Washing being one of the most elementary aspects of Jewish life. In fact, in observant circles, one doesn't say "Let's eat" but rather "let's wash") will be as unique as the Baal Shem Tov in his time". His students became frightened. "Perhaps we shouldn't bring children into the world?" Rabbi Nachman replied: "You do yours...when Mashiach comes, everyone will have a tikkun, going all the way back to Adam".