A sect of Christianity with some Jewish practices.
Messianic Judaism, (a branch of which is "Jews for Jesus") is a religious group that has tried to straddle the line between Judaism and Christianity.
According to this group, Jesus, or Yeshua in Aramaic, was the Messiah, and he died on behalf of the world's sins. They also believe that the Jews are the chosen people, and that the explicit laws of the Torah, such as observing Shabbat, holidays, and circumcision must be obeyed today.
The origins of this group can be traced back to the Hebrew Christian missions to the Jews in the 19th and early 20th centuries. By the 1960s and 70s Messianic Judaism was gaining popularity, known by many as “the Jesus people,” and eventually Jews for Jesus.
Because of Messianic Judaism's identification with Jesus, all of the major denominations of Judaism (Orthodox, Conservative, Reform, and Reconstructionist) have rejected Messianic Judaism as a form of Judaism. Within Christianity Messianic Judaism is sometimes seen as a group within the evangelical community, and sometimes seen as a separate sect. At times, various Christian leaders have publicly criticized Messianic Jews for their aggressive missionizing in the Jewish community and for misrepresenting themselves as Jews.
An Ethnic Church for Jews
Messianic Judaism is often presented as an ethnic church for Jews--somewhat like a Korean or Chinese church, but with outreach specific to Jews. However, most experts estimate that in most Messianic Jewish congregations only about half the members were born Jews.
Non-Jews who join a Messianic congregation may be asked to undergo a kind of conversion to Messianic Judaism, although many within the group believe that it's impossible to convert to Judaism. Messianic Jewish conversions are not considered valid by any Jewish denomination. Non-Jews who join Messianic congregations are sometimes called spiritual Jews, completed Jews, or Messianic gentiles.
Messianic Jews include the New Testament in their canon and believe that there is foreshadowing and predictions of Jesus in the Old Testament. Supersessionism, the belief that Jesus was the fulfillment of the promise made by God to the Jews in the Tanakh, is accepted by Messianic Jews. But unlike other Christian groups that believe in supersessionism, Messianic Jews maintain a desire to practice many of the commandments given in the Torah.
For example, believers in Messianic Judaism adhere to some of the laws given in the Torah, such as resting on Shabbat, not eating pork and shellfish, and observing biblical holidays like Sukkot and Passover. However, the faith does not adhere to rabbinic law, and eschews the authority of the Mishnah and Talmud.