Why has the study of Kabbalah been discouraged by some

All the rabbinical authorities have always agreed on the ultimate importance and truthfulness of the Kabbalah, they just did not agree on the way this knowledge should be disseminated. Some insisted that only a very selective group should be allowed to learn Kabbalah, and only after attaining a high level of purity and comprehension of all the other writings.

Others believed that it should be more accessible and taught to most Jews. During the 16th century with the coming of Shabbetai Tsevi who was called the “Kabbalistic Messiah”, the Jewish community was divided between his followers and the “non-believers”. After converting to Islam, this false Messiah caused a big deception and mistrust in the teachings of the Kabbalah. The rabbinical authorities of the time became even more severe with the learning of Kabbalah and some were even persecuted for learning or writing on the subject.