# Jacob Emden

Jacob Emden, also known as Ya'avetz (June 4, 1697 – April 19, 1776), was a leading German rabbi and talmudist who championed traditional Judaism in the face of the growing influence of the Sabbatean movement. He was widely acclaimed for his extensive knowledge.
Emden was the son of the hakham Tzvi Ashkenazi and a descendant of Elijah Ba'al Shem of Chełm. He spent most of his life in Altona (now part of Hamburg, Germany). His son, Meshullam Solomon, served as rabbi of the Hambro Synagogue in London and claimed authority as Chief Rabbi of the United Kingdom from 1765 to 1780.
The acronym Ya'avetz (יעב"ץ, also rendered Yaavetz) stands for Yaakov ben Tzvi (יעקב בן צבי).
Seven of his 31 works were published posthumously.

## Biography
### Early life and education

Jacob Emden (born Ashkenazi) was the fifth of his father's 15 children. Until the age of seventeen, he studied Talmud under his father, Tzvi Ashkenazi, a foremost rabbinic authority, first in Altona and later in Amsterdam (1710–1714). In 1715, he married Rachel, daughter of Mordecai ben Naphtali Cohen, rabbi of Ungarisch-Brod (Uherský Brod) in Moravia (modern Czech Republic), and continued his studies in his father-in-law's yeshivah.
Emden mastered all branches of Talmudic literature and later expanded his studies to philosophy, kabbalah, and grammar—even attempting to learn Latin and Dutch despite his view that secular studies should be limited to periods when Torah study was not feasible.

### Career

Emden initially spent three years in Ungarisch-Brod as a private Talmudic lecturer before taking up work as a dealer in jewelry and other goods—a trade that required extensive travel. Although he generally declined formal rabbinic positions, in 1728 he accepted the rabbinate of Emden, from which he later derived his name. He eventually returned to Altona, where he secured permission from the Jewish community to establish a private synagogue. Early on, he enjoyed cordial relations with Moses Hagiz, head of the Portuguese-Jewish community in Altona, though these later deteriorated due to calumnies. Similarly, his initially positive relations with the chief rabbi of the German community, Ezekiel Katzenellenbogen, later soured.
A few years later, Emden obtained permission from the King of Denmark to establish a printing press in Altona. He soon encountered controversy over his publication of the siddur Ammudei Shamayim, which contained harsh criticisms of influential local money changers. Despite receiving the approbation of the chief rabbi of the German communities, his opponents continued to denounce him.

### Ya'avetz Pen Name

In the preface to his work She'I'Las Yaavetz, Emden recounts how, as a child, he questioned why his father signed only as Tzvi (צבי) rather than including his father's name. His father explained that "Tzvi" stands for "Tzvi ben Yaakov" (צבי בן יעקב) and advised that when Emden began writing, he should sign as Ya'avetz (יעב"ץ), with the letters representing Yaakov ben Tzvi. The name Ya'avetz appears in 1 Chronicles both as a place name and a personal name.

## Sabbatean controversy

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Emden accused Jonathan Eybeschütz of being a secret Sabbatean. The controversy lasted several years, continuing even after Eybeschütz's death. Emden's assertion of Eybeschütz's heresy was chiefly based on the interpretation of some amulets prepared by Eybeschütz, in which Emden saw Sabbatean allusions. Hostilities began before Eybeschütz left Prague, and in 1751, when Eybeschütz was named chief rabbi of the three communities of Altona, Hamburg, and Wandsbek, the controversy reached the stage of intense and bitter antagonism. Emden maintained that he was at first prevented by threats from publishing anything against Eybeschütz. He solemnly declared in his synagogue the writer of the amulets to be a Sabbatean heretic and deserving of excommunication. In ''Megillat Sefer'', he even accuses Eybeschütz of having an incestuous relationship with his own daughter, and of fathering a child with her. However, there have been allegations that ''Megillat Sefer'' was tampered with, and had deliberately ridiculous accusations, as well as outlandish tales, written in to the original in order to make a mockery of Emden.
Clashes between opposing supporters occurred in the streets drawing the attention of the secular authorities. The majority of the community, including Aryeh Leib Epstein of Königsberg, favored Eybeschütz; thus the council condemned Emden as a slanderer. People were ordered, under pain of excommunication, not to attend Emden's synagogue, and he himself was forbidden to issue anything from his press. As Emden still continued his philippics against Eybeschütz, he was ordered by the council of the three communities to leave Altona. This he refused to do, relying on the strength of the king's charter, and he was, as he maintained, relentlessly persecuted. His life seeming to be in actual danger, in May 1751 he left the town and took refuge in Amsterdam, where he had many friends and where he joined the household of his brother-in-law, Aryeh Leib ben Saul, rabbi of the Ashkenazic community.
The controversy was heard by both the Senate of Hamburg and by the Royal Court of Denmark. The Hamburg Senate quickly found in favour of Eybeschütz. King Frederick V of Denmark asked Eybeschütz to answer a number of questions about the amulets. Conflicting testimony was put forward and the matter remained officially unresolved although the court sentenced the council of the three communities to pay a fine of one hundred thaler for civil unrest and ordered that Emden be allowed to return to Altona.
Emden then returned to Altona and took possession of his synagogue and printing-establishment, though he was forbidden to continue his agitation against Eybeschütz. The latter's partisans, however, did not desist from their warfare against Emden. They accused him before the authorities of continuing to publish denunciations against his opponent. One Friday evening (July 8, 1755) his house was broken into and his papers seized and turned over to the "Ober-Präsident" (royally imposed mayor), Henning von Qualen (1703–1785) [de]. Six months later von Qualen appointed a commission of three scholars, who, after a close examination, found nothing which could incriminate Emden. Eyebeschutz was re-elected as Chief Rabbi. In December of that year, the Hamburg Senate rejected both the King's decision and the election result. The Senate of Hamburg started an intricate process to determine the powers of Eybeschütz, as Chief Rabbi.
The truth or falsity of his denunciations against Eybeschütz cannot be proved; Gershom Scholem wrote much on this subject, and his student Perlmutter devoted a book to proving it. According to historian David Sorkin, Eybeschütz was probably a Sabbatean, and Eybeschütz's son openly declared himself to be a Sabbatean after his father's death. There is further background which suggests that Eybeschutz may have been a Sabbatean. In July 1725, the Ashkenazic beit din of Amsterdam issued a ban of excommunication on the entire Sabbatean sect (kat ha-ma’aminim) based partially on the discovery of certain Sabbatean writings by it. Rabbi Ezekiel Katzenellenbogen, the chief rabbi of the Three Communities was unwilling to attack Eybeschütz publicly, but stated that one of the Sabbatean texts found by the Amsterdam beit din "Va-Avo ha-Yom el ha-Ayyin” was authored by Eybeschütz and declared that the all copies of the work that were in circulation should be immediately burned. The recent discovery in Metz of notarial copies of the disputed amulets written by Eyebeschutz support Emden's view that these are Sabbatean writings.

## Other notable events

In 1756 the members of the Synod of Constantinov applied to Emden to aid in repressing the Sabbatean movement. As the Sabbateans referred much to the Zohar, Emden thought it wise to examine that book, and after a careful study he concluded that a great part of the Zohar was the production of an impostor.
Emden's works show him to have been possessed of critical powers rarely found among his contemporaries. He was strictly Orthodox, never deviating the least from tradition, even when the difference in time and circumstance might have warranted a deviation from custom. Emden's opinions were often viewed as extremely unconventional from the perspective of strictly traditional mainstream Judaism, though not so unusual in more free-thinking Enlightenment circles. Emden had friendly relations with Moses Mendelssohn, founder of the Haskalah movement, and with a number of Christian scholars.
In 1772 Frederick II, Duke of Mecklenburg-Schwerin, having issued a decree forbidding burial on the day of death, the Jews in his territories approached Emden with the request that he demonstrate from the Talmud that a longer exposure of a corpse would be against the Law. Emden referred them to Mendelssohn, who had great influence with Christian authorities and wrote in excellent German. Mendelssohn wrote the requested letter to the Duke, but privately complained to Emden that based on the Talmud, it seemed the Duke was correct. Emden wrote to him in strong terms, saying that it was ludicrous to assert that the custom of the entire Jewish people was blatantly incorrect, and told Mendelssohn that this kind of claim would only strengthen rumors of irreligiousness he (Mendelssohn) had aroused by his associations.

## Views

Emden was a traditionalist who responded to the ideals of tolerance being circulated during the 18th-century Enlightenment. He stretched the traditional inclusivist position into universal directions. Like Maimonides, he believed that monotheistic faiths have an important roles to play in God's plan for mankind, writing that "we should consider Christians and Muslims as instruments for the fulfilment of the prophecy that the knowledge of God will one day spread throughout the earth." Emden praised the ethical teachings of Christianity, considering them beneficial in removing the prevalence of idolatry and bestowing gentiles with a "moral doctrine". Emden also suggested that ascetic Christian practices provided additional rectification of the soul in the same way that Judaic commandments do.
In many ways, Emden was a nuanced figure who navigated the tension between rabbinic and external historical sources. Emden often tempered the exclusionist approach of scholars like Aviad Sar-Shalom Basilea, who outright rejected non-rabbinic sources, by cautiously engaging with external historical claims. For example, in addressing contradictions between Talmudic and historical accounts, Emden sometimes reinterpreted rabbinic texts to align with external evidence, as seen in his treatment of the Talmudic story about Nero’s conversion. He also critiqued R. Azariah de Rossi for uncritically accepting non-Jewish sources but stopped short of branding him a heretic, instead viewing him as misguided. Emden’s approach reflects a balance between preserving the authority of rabbinic literature and cautiously integrating external historical insights, making him a moderate voice in the debate over the historicity of rabbinic claims.
He theoretically advocated the taking of a concubine by a scholar since the sages of the Talmud stated "the greater the man, the greater his evil inclination" and cited many sources in support. He also suggested it might be permissible under certain circumstances for a Jewish man to cohabit with a single Jewish woman, provided that she is in an exclusive relationship with him that is public knowledge and where she would not be embarrassed to ritually immerse. He also wished to revoke the ban on polygamy instituted by Rabbeinu Gershom believing it erroneously followed Christian morals, although he admitted he lacked the power to do so.
Emden wrote that he owned books containing secular wisdom written in Hebrew, but that he would read them in the bathroom. He was opposed to philosophy and maintained that the views contained in The Guide for the Perplexed could not have been authored by Maimonides, but rather by an unknown heretic.

## Works

Jacob Emden’s corpus spans halakhic, liturgical, kabbalistic, and polemical writings—with some works jointly attributed to him and his father. His published writings include:
* Edut BeYaakov (Altona, Hamburg, 1756) – Addresses the alleged heresy of Eybeschütz, including the letter Iggeret Shum to the rabbis of the Four Lands.
* Shimmush (Amsterdam, 1758–62) – Comprises three works: Shoṭ la‑Sus, Meteg laHamor (against the influence of the Sabbateans), and Sheveṭ leGev Kesilim, a refutation of heretical demonstrations.
* Shevirat Luchot haAven (Altona, 1759) – A refutation of Eybeschütz’s Luchot Edut.
* Sechok haKesil, Yekev Ze'ev, and Gat Derukhah (Altona, 1762) – Three polemical works published in the *Hit'abbekut* of one of his pupils.
* Mitpachat Sefarim (Altona, 1761–68) – In two parts: the first demonstrates that part of the Zohar is a later compilation; the second criticizes works such as Emunat Hakhamim and Mishnat Hakhamim as well as various polemical letters.
* Herev Pifiyyot, Iggeret Purim, Teshuvot haMinim, and Zikkaron beSefer – On money changers and bankers (unpublished).
* Lechem Shamayim (Altona, 1728; Wandsbeck, 1733) – A commentary on the Mishnah with a treatise on Maimonides’ Mishneh Torah (Beit haBechirah).
* Iggeret Bikkoret (Altona, 1733) – Responsa.
* She'elat Ya'abetz (Altona, 1739–59) – A collection of 372 responsa.
* Siddur Tefillah (Altona, 1745–48) – An edition of the prayer book featuring commentary, grammatical notes, ritual laws, and treatises (including Beit‑El, Sha'ar haShamayim, and Migdal Oz); also contains the treatise Even Bochan and a critique of Menahem Lonzano’s Avodat Mikdash (titled Seder Avodah).
* Etz Avot (Amsterdam, 1751) – A commentary on Pirkei Avot, with grammatical notes compiled in Lechem Nekudim.
* Sha'agat Aryeh (Amsterdam, 1755) – A eulogy for his brother‑in‑law, Aryeh Leib ben Saul (rabbi of Amsterdam); also included in his Kishurim leYaakov.
* Seder Olam Rabbah and Seder Olam Zutta (Hamburg, 1757) – The texts of Seder Olam and Megillat Ta'anit, edited with critical notes.
* Mor uKetziah (Altona, 177?) – Novellæ on Orach Hayyim (with additional novellæ on Yoreh Deah, Even haEzer, and Hoshen Mishpat remaining unpublished).
* Tzitzim uFerachim (Altona, 1768) – A collection of kabbalistic articles arranged alphabetically.
* Luach Eresh (Altona, 1769) – Grammatical notes on the prayers and a critique of Solomon Hena’s Sha'arei Tefillah.
* Shemesh Tzedakah (Altona, 1772).
* Pesach Gadol, Tefillat Yesharim, and Ḥoli Ketem (Altona, 1775).
* Sha'arei Azarah (Altona, 1776).
* Divrei Emet uMishpaṭ Shalom (Altona, 1776).
* Megillat Sefer (Warsaw, 1897) – Contains biographies of himself and his father.
* Kishurim leYaakov – A collection of sermons.
* Marginal novellæ on the Babylonian Talmud.
* Emet LeYaakov (Kiryas Joel, 2017) – Notes on the Zohar and assorted works, including Dei Rossi’s Meor Einayim.
His unpublished rabbinical writings include:
* Tza'akat Damim – A refutation of the blood libel in Poland.
* Hilkheta liMeshicha – A responsum to R. Israel Lipschütz.
* Mada'ah Rabbah.
* Gal‑Ed – A commentary on Rashi and the Targum of the Pentateuch.
* Em laBinah – A commentary on the entire Bible.
* Em laMikra velaMasoret – Also a commentary on the Bible.

### Emden Siddur

20th-century printings of the Emden Siddur exist, notably the Lemberg edition (1904) and the Augsburg edition (1948), both bearing the cover title Siddur Beis Yaakov (also anglicized as Siddur Bet Yaakov; Hebrew: סידור בית יעקב). The covers identify the work as being by "Jacob from Emden" (יעקב מעמדין). The 472-page Lemberg 1904 printing includes Tikun Leil Shavuot on pages 275–305 and is considerably larger than Emden’s Shaarei Shamayim siddur.

#### Shaarei Shamayim

A physically smaller siddur, reprinted in Israel in 1994, was titled Siddur Rebbe Yaakov of Emden (Hebrew: סידור רבי יעקב מעמדין) on the upper half of the cover and Siddur HaYaavetz Shaarei ShaMaYim (סדור היעב"ץ שערי שמים) elsewhere. Its commentary is less detailed than that of the full Emden Siddur—for example, it omits Tikkun Leil Shavuot. This edition is presented as a two-volume set.