Hasidism () or Hasidic Judaism is a religious movement within Judaism that arose in the 18th century as a spiritual revival movement in contemporary Western Ukraine before spreading rapidly throughout Eastern Europe. Today, most of those affiliated with the movement, known as hassidim, reside in Israel and in the United States, and to a lesser extent in Canada, the United Kingdom, Argentina and Belgium.

Israel Ben Eliezer, the "Baal Shem Tov", is regarded as its founding father, and his disciples developed and disseminated it. Present-day Hasidism is a sub-group within Haredi Judaism and is noted for its religious conservatism and social seclusion. Its members aim to adhere closely both to Orthodox Jewish practice – with the movement's own unique emphases – and the prewar lifestyle of Eastern European Jews. Many elements of the latter, including various special styles of dress and the use of the Yiddish language, are nowadays associated almost exclusively with Hasidism.

Hasidic thought draws heavily on Lurianic Kabbalah, and, to an extent, is a popularization of it. Teachings emphasize God's immanence in the universe, the need to cleave and be one with him at all times, the devotional aspect of religious practice, and the spiritual dimension of corporeality and mundane acts. Hasidim, the adherents of Hasidism, are organized in independent sects known as "courts" or dynasties, each headed by its own hereditary male leader, a Rebbe. Reverence and submission to the Rebbe are key tenets, as he is considered a spiritual authority with whom the follower must bond to gain closeness to God. The various "courts" share basic convictions, but operate apart and possess unique traits and customs. Affiliation is often retained in families for generations, and being Hasidic is as much a sociological factor – entailing birth into a specific community and allegiance to a dynasty of Rebbes – as it is a religious one. There are several "courts" with many thousands of member households each, and hundreds of smaller ones. , there are roughly 250,000 followers of Hasidic Judaism worldwide, about 2% of the global Jewish population.

Etymology The terms hasid and hasidut, meaning "pietist" and "piety", have a long history in Judaism. The Talmud and other old sources refer to the "Pietists of Old" (Hasidim haRishonim) who would contemplate an entire hour in preparation for prayer. The phrase denoted extremely devoted individuals who not only observed the Law to its letter, but performed good deeds even beyond it. Adam himself is honored with the title, in tractate Eruvin 18b by Rabbi Meir: "Adam was a great hasid, having fasted for 130 years." The first to adopt the epithet collectively were apparently the hasidim in Second Temple period Judea, known as Hasideans after the Greek rendering of their name, who perhaps served as the model for those mentioned in the Talmud. The title continued to be applied as an honorific for the exceptionally devout. In 12th-century Rhineland, or Ashkenaz in Jewish parlance, another prominent school of ascetics named themselves hasidim; to distinguish them from the rest, later research employed the term Ashkenazi Hasidim. In the 16th century, when Kabbalah spread, the title also became associated with it. Jacob ben Hayyim Zemah wrote in his glossa on Isaac Luria's version of the Shulchan Aruch that, "One who wishes to tap the hidden wisdom, must conduct himself in the manner of the Pious."

The movement founded by Israel Ben Eliezer in the 18th century adopted the term hasidim in the original connotation. But when the sect grew and developed specific attributes, from the 1770s, the names gradually acquired a new meaning. Its common adherents, belonging to groups each headed by a spiritual leader, were henceforth known as Hasidim. The transformation was slow: The movement was at first referred to as "New Hasidism" by outsiders (as recalled in the autobiography of Salomon Maimon), to separate it from the old one, and its enemies derisively mocked its members as Mithasdim, "[those who] pretend [to be] hasidim". Yet, eventually, the young sect gained such a mass following that the old connotation was sidelined. In popular discourse, at least, "Hasid" came to denote someone who follows a religious teacher from the movement. It also entered Modern Hebrew as such, meaning "adherent" or "disciple". One was not merely a Hasid anymore, observed historian David Assaf, but a Hasid of someone or some dynasty in particular. This linguistic transformation paralleled that of the word tzaddik, "righteous", which the Hasidic leaders adopted for themselves – though they are known colloquially as Rebbes or by the honorific acronym Admor. Originally denoting an observant, moral person, in Hasidic literature, tzaddik became synonymous with the often hereditary master heading a sect of followers.

Hasidic philosophy

Distinctions

The lengthy history of Hasidism, the numerous schools of thought therein, and its definitive use of homiletic literature and sermons – comprising numerous references to earlier sources in the Torah, Talmud, and exegesis as a means to grounding itself in tradition – to convey its ideas make the isolation of a common doctrine highly challenging to researchers. As noted by Joseph Dan, "Every attempt to present such a body of ideas has failed". Even motifs presented by scholars in the past as unique Hasidic contributions were later revealed to have been common among both their predecessors and opponents, all the more so regarding many other traits that are widely extant – these play, Dan added, "a prominent role in modern non-Hasidic and anti-Hasidic writings as well".Joseph Dan, Hasidism: Teachings and Literature, The YIVO Encyclopedia of Jews in Eastern Europe The difficulty of separating the movement's philosophy from that of its main inspiration, Lurianic Kabbalah, and determining what was novel and what merely a recapitulation, also baffled historians. Some, like Louis Jacobs, regarded the early masters as innovators who introduced "much that was new if only by emphasis";Louis Jacobs, Basic Ideas of Hasidism, in: Hasidism, Encyclopedia Judaica, 2007. Volume 8, p. 408. others, primarily Mendel Piekarz, argued to the contrary that but a little was not found in much earlier tracts, and the movement's originality lay in the manner it popularized these teachings to become the ideology of a well-organized sect.Mendel Piekarz, Ben ideʼologyah li-metsiʼut, Bialik Institute (1994), . pp. 151–152; Dynner, Men of Silk, p. 27.

Among the traits particularly associated with Hasidism is the importance of joy and happiness at worship and religious life. However, the sect undoubtedly stressed this aspect and still possesses a clear populist bent. Another example is the value placed on the simple, ordinary Jew in supposed contradiction with the favouring of elitist scholars beforehand; such ideas are common in ethical works far preceding Hasidism. The movement did for a few decades challenge the rabbinic establishment, which relied on the authority of Torah acumen, but affirmed the centrality of study very soon. Concurrently, the image of the Misnagdim, a term coined for those opposed to Hasidism, as dreary intellectuals who lacked spiritual fervour and opposed mysticism, is likewise unfounded. Neither did Hasidism, often portrayed as promoting healthy sensuality, unanimously reject the asceticism and self-mortification associated primarily with its rivals. Joseph Dan ascribed all these perceptions to so-called "Neo-Hasidic" writers and thinkers, like Martin Buber. In their attempt to build new models of spirituality for modern Jews, they propagated a romantic, sentimental image of the movement. The "Neo-Hasidic" interpretation influenced even scholarly discourse to a great degree, but had a tenuous connection with reality.

A further complication is the divide between what researchers term "early Hasidism", which ended roughly in the 1810s, and established Hasidism since then onwards. While the former was a highly dynamic religious revival movement, the latter phase is characterized by consolidation into sects with hereditary leadership. The mystical teachings formulated during the first era were by no means repudiated, and many Hasidic masters remained consummate spiritualists and original thinkers; as noted by Benjamin Brown, Buber's once commonly accepted view that the routinization constituted "decadence" was refuted by later studies, demonstrating that the movement remained very much innovative.See, for example, Benjamin Brown, Hasidism Without Romanticism: Mendel Piekarz's Path in the study of Hasidism. pp. 455–456. Yet many aspects of early Hasidism were de-emphasized in favour of more conventional religious expressions, and its radical concepts were largely neutralized. Some Rebbes adopted a relatively rationalist bent, sidelining their explicit mystical, theurgical roles, and many others functioned almost solely as political leaders of large communities. As to their Hasidim, affiliation was less a matter of admiring a charismatic leader as in the early days, but rather birth into a family belonging to a specific "court".Assaf, Regal Way, pp. 49–55, 63–67; Dynner, Men of Silk, pp. 117–121.

Immanence

The most fundamental theme underlying all Hasidic theory is the immanence of God in the universe, often expressed in a phrase from Tikunei haZohar, (Aramaic: "no site is devoid of Him"). This panentheistic concept was derived from Lurianic discourse, but greatly expanded in the Hasidic one. In the beginning, in order to create the world, God contracted (Tzimtzum) his omnipresence, the Ein Sof, leaving a Vacant Void (), bereft of obvious presence and therefore able to entertain free will, contradictions and other phenomena seemingly separate from God Himself. These would have been impossible within his original, perfect existence. Yet, the very reality of the world which was created in the Void is entirely dependent on its divine origin. Matter would have been null and void without the true, spiritual essence it possesses. Just the same, the infinite Ein Sof cannot manifest in the Vacant Void, and must limit itself in the guise of measurable corporeality that may be perceived.Rachel Elior, יש ואין - דפוסי יסוד במחשבה החסידית, in: Masuʼot : meḥḳarim be-sifrut ha-ḳabalah ube-maḥshevet Yiśraʼel, Bialik Institute (1994), . pp. 53–54.

Thus, there is a dualism between the true aspect of everything and the physical side, false but ineluctable, with each evolving into the other: as God must compress and disguise himself, so must humans and matter in general ascend and reunite with the Omnipresence. Rachel Elior quoted Shneur Zalman of Liadi, in his commentary Torah Or on Genesis 28:22, who wrote that "this is the purpose of Creation, from Infinity to Finitude, so it may be reversed from the state of Finite to that of Infinity". Kabbalah stressed the importance of this dialectic, but mainly (though not exclusively) evoked it in cosmic terms, referring for example to the manner in which God progressively diminished himself into the world through the various dimensions, or Sephirot. Hasidism applied it also to the most mundane details of human existence. All Hasidic schools devoted a prominent place in their teaching, with differing accentuation, to the interchanging nature of Ein, both infinite and imperceptible, becoming Yesh, "Existent" – and vice versa. They used the concept as a prism to gauge the world, and the needs of the spirit in particular. Elior noted: "Reality lost its static nature and permanent value, now measured by a new standard, seeking to expose the Godly, boundless essence, manifest in its tangible, circumscribed opposite."Elior, p. 56.