Rabbi, cantor and gabbai are the three main types of Jewish clergy. Traditionally, a synagogue or shul has a rabbi, and it may have a cantor. Some congregations also have a gabbai, which translates to a manager during the service. Larger congregations may also have assistants to fill many of these roles. In Judaism, the clergy system is not hierarchical.

The Rabbi

While rabbis will generally complete a formal course of Torah study, they hold no more religious authority within a congregation than any other member. Within the various denominations of Judaism -- Orthodox, Conservative and Reform -- the roles of the rabbi differ. Traditionally a rabbi would be a scholar, a student and a teacher, but in contemporary society, some view the rabbi as the conduit to the wider, non-Jewish, community. Regardless of contemporary thinking on the rabbi's roles, the rabbi is ideally a Torah scholar who uses this knowledge to guide his community.

Cantor or Hazan

Many synagogues also have a cantor, or hazan. Historically, the term simply meant someone qualified to lead the congregation in prayer, but in the Western tradition, the term came to mean someone who had special musical qualifications. Problematically for cantors, the issue of their motivation has sometimes been held in question. Are they leading the congregation in solemn prayer through the gift of voice, or are they using their voice as a means of gaining the adulation of the congregation? While the former is solemn, the latter has been described as "disgraceful."

Gabbai

Colloquially a gabbai is best thought of as a manager. The gabbai's job is to follow the readings of the Torah, which lacks both vowels and punctuation in Hebrew, in a book that contains both. A Gabbai also manages other portions of the service. They announce the Hebrew names of members of the congregation who come to the pulpit to read from the Torah. They also ensure that the Torah is rolled to the correct place for the day's or week's reading. They determine which member of the congregation will read the Haftorah portion, a weekly reading from Prophets that accompanies the week's Torah reading.

Sharing Responsibilities

Since Jewish ceremonies lack a hierarchy, many or all of the functions of rabbi, cantor or gabbai may be shared among the members of the congregation. Where the Torah is read only by men, as in an Orthodox synagogue, the only requirement is that those who read from the Torah are over the age of 13. At that age they are "bar mitzvah," or a son of the law. If an Orthodox synagogue were to lack a rabbi for a ceremony, the cantor or gabbai, or any other Jewish male over the age of 13 could lead the ceremony. In Conservative and Reform synagogues, these functions can be, and often are, performed by women, with no restriction on their participation in any ceremony or recognition in any role.