Returning to the Talmud Landau was disturbed by the increasing influence of non-Talmudic sources on the Jewish community. He believed that many kabbalistic concepts were being understood in a heretical fashion, and was especially concerned with the prospect of the kabbalistic ideology of the Sabbatean movement infiltrating the populace. Landau frequently spoke against teaching Kabbalah to the masses, and was echoed in this regard by his student,
Elazar Fleckeles, who praised the government for instituting laws limiting the study of kabbalah. In his responsa, when asked about matters that had no source in the Talmud, Landau would often respond, "it is not my way to study any issue which is not discussed in the Talmud". He responded in such a manner to inquiries about the ethical will of Rabbi
Yehuda haChasid, which contains various instructions not found in the Talmud, a question about the proper manner of writing certain letters in the Torah scroll according to kabbalistic literature, and other similar questions.
Opinion on the Zohar In his
sefer Derushei HaTzlach, Landau argued that the
Zohar can not be considered reliable, since it only came into the hands of the Jewish people many hundreds of years after
Rashbi's death, and thus lacks an unbroken
mesorah as to its authenticity, among other reasons.
Clashes with the haskalah movement Landau condemned the
haskalah movement in harsh terms. In numerous public sermons, he campaigned against the study of heretical philosophy. He particularly singled out
Hartwig Wessely for criticism after the publication of the latter's ''Divrei Shalom V'emes'', which advocated abandoning the traditional Jewish educational system, in favor of one with an emphasis on secular studies.
Opposition to Chasiddus Landau was a staunch opponent of the nascent
Hasidic movement. In one response, he writes "...In this generation of ours [people] have abandoned God’s Torah and the source of living waters–the two Talmuds, Bavli and Yerushalmi–to dig for themselves broken cisterns. And in the haughtiness of their hearts they exalt themselves; each one says "I am the one who sees, to me the gates to heaven have opened, and on my account the world is sustained". These [people] are the destroyers of the generation and of this orphaned generation I say that God's ways are just, and the righteous shall walk in them, and the
Chasidim shall stumble in them [This is an alteration of Hoshea 14:14, in which the prophet says that
sinners will stumble in them.]..."
Opposition to the Sabbatean movement According to Sid Z. Leiman and Maoz Kahana, although Landau was extremely active in combating the Sabbatean movement, he believed the most effective means of eradicating it would be to aggressively counter overt Sabbateanism, while ignoring those Sabbateans who stayed hidden. Simultaneously, Landau sought to weaken the appeal of kabbalah (the study of which often lured people to the Sabbatean movement). Thus, Landau aimed to deprive the Sabbateans of any platform, and cause the Sabbatean movement to wither on its own. Besides the specific debate over the status of Jonathan Eybeschuetz, Jacob Emden expressed strong disagreement with Landau's approach, advocating instead for a far more aggressive anti Sabbatean strategy. == See also ==