When a person reads a book that was written by a Kabbalist, he in fact, connects himself with the upper management. And because the writer wrote the book while being in the upper world, as well as in ours, his attainment reaches the upper world, but the text is in words of our world, written with pen on paper. This way he connects the two worlds with one another.
Hence, when we read something that a Kabbalist wrote, we connect through it with the spiritual degree that he was in when he wrote it. This way, a person awakens in himself an illumination of sublime energy – the upper light. As the light descends on a person, it creates around him a sort of ‘spiritual shell’ that protects him.