"The role of a rabbi is not essentially a sacramental, purely religious one.
Unlike the Catholic priest, who serves by virtue of holy orders (and actually holds in his hand the sole authority to perform the sacraments), the Jewish rabbi has no essential function that cannot be performed by someone else.
In theory at least, a Jewish community could carry on its whole spiritual and religious life without the services of a rabbi, who, being learned in the Torah and Jewish law, has merely to help the members of the community when a religious problem arises."
--Rabbi Adin Steinsaltz
From The Strife of the Spirit by Rabbi Adin Steinsaltz