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Judaism

The Torah contains a few specific regulations that apply to polygamy, such as Exodus 21:10: "If he take another wife for himself; her food, her clothing, and her duty of marriage, shall he not diminish". Deuteronomy 21:15–17, states that a man must award the inheritance due to a first-born son to the son who was actually born first, even if he hates that son's mother and likes another wife more; and Deuteronomy 17:17 states that the king shall not have too many wives. Despite its prevalence in the Hebrew Bible, some scholars do not believe that polygyny was commonly practiced in the biblical era because it required a significant amount of wealth. Michael Coogan (and others), in contrast, states that "Polygyny continued to be practiced well into the biblical period, and it is attested among Jews as late as the second century CE ".

The Dead Sea Scrolls show that several smaller Jewish sects forbade polygamy before and during the first century. The Temple Scroll (11QT LVII 17–18) seems to prohibit polygamy. The rabbinical era, beginning with the destruction of the Second Temple in 70 CE, saw a continuation of some degree of legal acceptance for polygamy. Statements in the Talmud include, " 'Be thou betrothed to half of me,' she is betrothed; 'Half of thee be betrothed to me,' she is not betrothed" and elsewhere, "A man may marry wives in addition to the first wife; provided only that he possesses the means to maintain them", though another opinion in the Talmud requires divorcing a first wife before taking a second. In practice, polygamy was extremely rare in Jewish society in the Talmudic period.

Later on, the Jewish codices began a process of restricting polygamy in Judaism. Most notable, though more specifically for Ashkenazi Jews, was the synod of Rabbeinu Gershom. About 1000 CE he called a synod which decided the following particulars: (1) prohibition of polygamy; (2) necessity of obtaining the consent of both parties to a divorce; (3) modification of the rules concerning those who became apostates under compulsion; (4) prohibition against opening correspondence addressed to another. Some Sephardic Jews such as Abraham David Taroç were known to have several wives.

Polygamy was common among Jewish communities in the Levant, possibly due to the influence of Muslim society, with 17% of divorce claims by women being due to complaints over husbands taking additional wives. According to R. Joseph Karo (16th century author of the last great codification of Jewish law, the Shulchan Aruch), and many other rabbis from Safed, the ban of Rabbeinu Gershom had expired, and therefore even Ashkenazim could marry additional wives. Even in instances where the husband made prenuptial agreements not to marry additional wives, local rabbis found loopholes to allow them to do so anyway.

The assembly led by Rabbeinu Gershom instituted a ban on polygamy, but this ban was not well received by the Sephardic communities. In addition to the ban, Gershon also introduced a law called Heter meah rabbanim which allows the men to remarry with the permission from one hundred rabbis from different countries.

In the modern day, polygamy is generally not condoned by Jews. Ashkenazi Jews have continued to follow Rabbenu Gershom 's ban since the 11th century. Some Mizrahi Jewish communities (particularly Yemenite Jews and Persian Jews) discontinued polygyny more recently, after they immigrated to countries where it was forbidden or illegal. Israel prohibits polygamy by law. In practice, however, the law is loosely enforced, primarily to avoid interference with Bedouin culture, where polygyny is practiced. Pre-existing polygynous unions among Jews from Arab countries (or other countries where the practice was not prohibited by their tradition and was not illegal) are not subject to this Israeli law. But Mizrahi Jews are not permitted to enter into new polygamous marriages in Israel. However polygamy may still occur in non-European Jewish communities that exist in countries where it is not forbidden, such as Jewish communities in Iran and Morocco.

Late Sephardic chief rabbi Ovadia Yosef supported the legalisation by the Israeli government of polygamy and the practice of pilegesh (the keeping of concubines). Tzvi Zohar, a professor from the Bar-Ilan University, recently suggested that based on the opinions of leading halachic authorities, the concept of concubines may serve as a practical halachic justification for premarital or non-marital cohabitation.