Gaon Hai

Hai ben Sherira (Hebrew: האי/י בר שרירא) better known as Hai Gaon (Hebrew: האי/י גאון, חאיי גאון), was a medieval Jewish theologian, rabbi and scholar who served as Gaon of the Talmudic academy of Pumbedita during the early 11th century. He was born in 939 and died on March 28, 1038. He received his Talmudic education from his father, Sherira ben Hanina, and in early life acted as his assistant in teaching. In his forty-fourth year he became associated with his father as "''av bet din''," and with him delivered many joint decisions. According to '' Sefer HaKabbalah'' of Rabbi Abraham ben David (Ravad), he was the last of the ''Geonim''.

Appointment as Gaon

As a consequence of the calumnies of their antagonists Hai and his father were imprisoned together, and their property was confiscated, by the caliph al-Qadir in 997 C.E. The imprisonment was brief, but shortly thereafter (in 998) the aged and infirm Sherira appointed his son to the position of gaon. Hai's installation was greeted with great enthusiasm by the Jewish population. An old tradition says that on the Sabbath after Sherira's death, at the end of the reading of the weekly lesson, the passage in which Moses asks for an able follower was read in honor of Hai. Thereupon, as haftarah, the story of Solomon's accession to the throne was read, the last verse being modified as follows: "And Hai sat on the throne of Sherira his father, and his government was firmly established." Hai remained gaon until his death in 1038. He was celebrated by the Spanish poet Solomon ibn Gabirol and by Samuel ha-Nagid.

Writings

Responsa

Hai ben Sherira's chief claim to recognition rests on his numerous responsa, in which he gives decisions affecting the social and religious life of the Diaspora. Questions reached him from Germany, France, Iberia, Anatolia, the Maghreb, and even India and Ethiopia. His responsa, more than 800 in number, deal with civil law, especially laws concerning women, with ritual, holidays, and so on. Many of them contain explanations of certain halakhot, aggadot, and Talmudic matters. In halakhic decisions he quotes the Jerusalem Talmud, but without ascribing any authority to it. Many of his responsa may have been written in Arabic; only a few of them have been preserved.

Legal treatises

Hai ben Sherira codified various branches of Talmudic law. His works include:
* An Arabic treatise on sales and transactions, translated into Hebrew by Isaac Albargeloni with the title ''HaMekach vehaMimkar'' (; 1078).
* ''Sefer ha-Mashkon,'' a treatise on mortgage law, anonymously translated into Hebrew
* ''Mishpetei haTena'im,'' a treatise on conditions, also anonymously translated into Hebrew.
These three treatises were published together (Venice, 1604); later editions also contain commentaries by Eleazar ben Aryeh (Vienna, 1800) and by Hananiah Isaac Michael Aryeh (Salonica, 1814). Another anonymous translation of them exists in manuscript under the title "Dinei Mamonot."

According to Rabbi David Azulai, Hai also wrote in Arabic ''Sha'arei Shevu'ot,'' a treatise on oaths. According to another Hebrew source, the original title was ''Kitab al-Aiman.'' This treatise was twice anonymously translated into Hebrew: (1) ''Mishpeṭe Shebu'ot'' (Venice, 1602; Altona, 1782); (2) ''Sefer Mehubbar be-Kotzer Min ha-Dinim be-Bi'ur Kelalim we-'liqarim be-Helqe Hiyyub la-Shebu'ah'' ''Sha'arei Shevu'ot'' was metrically arranged by an anonymous writer, probably of the 13th century, under the title ''Sha'arei Dinei Mamonot ve-Sha'arei Shevu'ot,'' and by Levi ben Jacob Alkalai.

Hai's treatise on boundary litigations, "Metzranut," is known only through quotations.

''Hilkot Tefillin, Siddur Tefillah'' and ''Metibot'' are also quoted as his.

Commentaries on the Mishnah

Hai ben Sherira's philological abilities were directed towards interpreting the Mishnah; of this work only the portion on Seder Tohorot is extant; it was published by T. Rosenberg in "Qobetz Ma'aseh" (Berlin, 1856). This commentary contains especially interesting linguistic notes, Arabic and Aramaic being often adduced for comparison. The author quotes the Mishnah, the two Talmuds, the Tosefta, the Sifra, Targums Onkelos and Jonathan, the Septuagint, the works of Saadia Gaon, the ''Sifre Refu'ah,'' and other anonymous sources. He also quotes his own commentary on Zera'im (p. 34) and on Baba Batra (p. 43). These quotations, and many others cited by the Arukh, prove that the commentary extended to the whole Mishnah, containing among other explanations historical and archeological notes. Some passages of the commentary are quoted by Alfasi and Hananel on Yoma, and by