Answer
Judaism is the traditional religion for Jews, but it may be practiced by non-Jews as well. Not all Jews practice Judaism, of course; some reject Judaism in favor of other religions or no religion at all. Judaism is a religion that emphasizes lifestyle and values more than beliefs, so correct doctrine is not emphasized nearly as much as correct behavior. Many Jews will maintain their connection to a synagogue and continue to observe certain practices and traditions while rejecting many of the doctrines that may be taught there. One should not assume that attendance at a particular synagogue signifies acceptance of all that is taught there. Of course, this is true for Christian church attendance as well, but it seems to be even more prevalent within Judaism.
A couple of centuries ago, Orthodox Judaism was the only form of Judaism. Today, Judaism is made up of three main “branches”: Orthodox (very traditional), Reform (also known as Liberal or Progressive), and Conservative, which charts a course between the other two. Naturally, there are offshoots, variations, and even hybrids of these three. Most synagogues are designated by the branch title, similar to a denominational name on a church.
Finally, there are secular or non-religious Jews (also called humanistic or non-theistic Jews) who maintain a Jewish ethnic identity through the observance of many Jewish traditions. Originally, those traditions had a religious purpose, but secular Jews attach absolutely no religious significance to them today. Secular Jews make up a significant portion of the Jewish population in the United States.
What is today called Orthodox Judaism for most of history was simply called Judaism. The term Orthodox, which literally means “right opinion,” began to be used in the late 18th and early 19th centuries to distinguish it from other approaches to Judaism that had begun to develop. Orthodox was first used as a pejorative term by more progressive Jews but came to be embraced by the traditional adherents of Judaism.
Orthodox Judaism emphasizes living according to the Law of Moses (the Torah), as it has been interpreted by the authoritative rabbinic tradition. According to Orthodox Judaism, in addition to the written Law, Moses also received the correct interpretation of the Law, which has been handed down by oral tradition through the rabbis until it was finally written down in the Mishnah, dating from the 2nd century AD.
Since that time, the Mishnah has been further developed and interpreted. The Mishnah and its additional histories, commentaries, and applications are known as the Talmud, of which there are two versions: the Jerusalem Talmud and the Babylonian Talmud. Orthodox Judaism considers the Babylonian Talmud to be more authoritative. The study of the Talmud is essential to Orthodox Judaism, even more important than the study of the Torah.
Rabbinic commentary on the Talmud has accrued over the years and has come to be known as the halakha. The halakha provides authoritative instruction for Orthodox Jews on religious and civil practices and is binding upon the individual and the community. Some of the distinctive practices of Orthodox Judaism include gender-segregated prayer, a refusal to travel on the Sabbath, and maintaining strict kosher observance.
There are two variations within Orthodox Judaism. Modern Orthodoxy maintains all the distinctives of Orthodoxy but freely interacts with the society at large and considers a secular education to be important. Ultra-Orthodoxy (a term that some find offensive) or Haredi Judaism tends to insulate itself from secular society, focus on religious education, wear distinctive clothing (normally black suits and white shirts for men and carefully modest dress for women), and primarily speak Yiddish. Adherents to this form of Judaism in the United States will often live in enclaves in larger cities. A subset of Haredi Judaism is Hasidic Judaism, which is then divided into various sects. Each sect within Hasidic Judaism is led by a rebbe who is believed to have direct access to God. Kabbalah, which is often described as “Jewish mysticism,” is also central to Hasidic Judaism.
While this article provides a basic overview of Orthodox Judaism, it is important not to make assumptions about an individual because of a label or perceived category. A Christian who is seeking to interact with an Orthodox Jew should first ask questions to get to know that person as an individual and to learn the specifics of that person’s beliefs and values.
