There are three reasons for the concealment of Kabbalah:
In every single detail in Kabbalah, these three prohibitions are simultaneously imposed.
The ban, no necessity to disclose, means that the disclosure of the wisdom brings no benefit. The only possible benefit might be the case of an obvious benefit for society. People who live by the principle, “So what?” (I did what I did and there is no harm in it), engage in and force others to engage in details that are utterly unnecessary. They are the source of much suffering in the world. Hence, Kabbalists accepted only those students who could keep it secret and refrain from needlessly disclosing it.
The ban, impossible to disclose, stems from limitations of the language that cannot describe subtle spiritual concepts. Since all verbal attempts are doomed to fail and lead to erroneous conclusions that will only confuse the student, the revelation of these secrets requires special permission from Above.
A special permission from above is described in the works of the great Kabbalist, the Ari: “Know that the souls of great Kabbalists are filled with the Outer (Surrounding) Light or with the Inner Light (filling). The souls filled with the Surrounding Light have the gift to expound on the secrets by vesting them in words, so that only the worthy can understand it.
“The soul of the great Kabbalist Rashbi (Rabbi Shimon Bar-Yochai, lived in the 2nd Century BCE), the author of The Book of Zohar, was filled with the Surrounding Light; hence, he had the power to explain the secrets of the universe in such a way that when he spoke before the Great Assembly, only the worthy understood him. Therefore, he alone received the divine permission to write The Book of Zohar. Although Kabbalists who lived before him knew more, they did not have his gift of enrobing spiritual concepts in words.”
Thus we see that the conditions for divulging Kabbalah depend not on the knowledge of a Kabbalist, but on the attributes of the Kabbalist’s soul. Only because of this does a Kabbalist receive instruction from Above to disclose a certain part of Kabbalah.
That is why we do not find any fundamental works on Kabbalah composed prior to The Book of Zohar. Those that are available contain only vague and inconsequential hints. After Rashbi, only the Ari was allowed to reveal another part of Kabbalah. Although Kabbalists who had lived before him probably knew a lot more than he did, they did not receive permission from Above.
The ban, The Creator’s personal secret, means that Kabbalistic secrets are only revealed to those who are devoted to the Creator and revere Him. This is the most important reason for keeping Kabbalah’s secrets from a wide circle of people. Many frauds used Kabbalah in their own interests by luring simpletons with soothsaying, making amulets, “saving” people from the evil eye, and other so-called miracles.
Originally Kabbalah was concealed for this very reason. Therefore, the true Kabbalists committed to subjecting their disciples to very stringent tests. This explains why even the few people in every generation granted permission to study Kabbalah were sworn not to reveal even a small detail of it, which fell under the three above-listed bans.
However, we should not think that these three bans divide Kabbalah into three parts. On the contrary, every part, word, concept, and definition in Kabbalah falls under this division into three types of concealment of the genuine meaning, and it is constantly effective in this science.
The question does arise: if this secret science was so thoroughly concealed, how did all the Kabbalistic compositions appear? The answer is: the first two bans differ from the third, because the last ban is the strictest of all. The first two parts are not permanently valid because, depending on the external social reasons, the condition, no necessity to disclose, sometimes turns into the instruction, There is a need to disclose. With the development of humanity, or due to the received permission (as in the cases of the Ari, Rashbi and, to a lesser extent, other Kabbalists), genuine books on Kabbalah begin to appear.