The way of Kabbalah consists in relying on the minds of those who already attained the ultimate goal, as if it was our own life experience. But how can I be sure that the mind I put my faith in is true? On the other hand, if I don’t use the wise mind the way I follow the physician’s advice, I condemn myself to a long way of suffering, like a sick man, who refuses to follow his doctor’s instructions and starts learning medicine, unaware that he may die long before he has some idea of it. Such is the way of suffering in comparison with the way of Kabbalah. He, who has no faith in the wisdom of Kabbalah, may try to independently attain this wisdom by going through life troubles, whereas there is experience, which tremendously accelerates the process, allows developing the sensation of realization of evil not by his own choice, but through the efforts made for acquiring a good environment.
Man is born in this world so as to discover the upper realm in the course of his life. Then he exists in both worlds and, after his body dies, feels the spiritual world as much as he could feel it while living in his physical body. If man failed to enter the spiritual world during his lifetime, his soul descends to this world again, incarnates in a new biological body with the same purpose. The soul can reveal the upper world only while being in a physical body.
Courtesy of http://www.youtube.com/watch?v=JgiGrXpOhYg