Although not mentioning the Noahide Laws directly by name, the Christian convention of Apostles and elders in Jerusalem mentioned in Acts 15 appears to validate the idea that all gentiles follow the constraints established by the covenant of Noah. This is what appears to be the case, as verse 15:20 lists a similar set of constraints to be applied to the gentiles that are converted to Christianity as what is contained in the Noahide laws.

The sources and process of Halakha

The boundaries of Jewish law are determined through the halakhic process, a religious-ethical system of legal reasoning. Rabbis generally base their opinions on the primary sources of Halakha as well as on precedent set by previous rabbinic opinions. The major sources and genre of Halakha consulted include:

The foundational Talmudic literature (especially the Mishna and the Babylonian Talmud) with commentaries; The post-Talmudic codificatory literature, such as Maimonides' Mishneh Torah and the Shulkhan Arukh with commentaries; Regulations and other "legislative" enactments promulgated by rabbis and communal bodies: Gezeirah: "preventive legislation" of the Rabbis, intended to prevent violations of the commandments Takkanah: "caring legislation", practices instituted by the Rabbis not based (directly) on the commandments Minhag: Customs, community practices, and customary law, as well as the exemplary deeds of prominent (or local) rabbis; The ''she'eloth u-teshuvoth (responsa, literally "questions and answers") literature. Dina d'malchuta dina ("a law of the land is law"): an additional source of Halakha, being the principle recognizing non-Jewish laws and non-Jewish legal jurisdiction as binding on Jewish citizens, especially for many areas of commercial, civil and criminal law, provided that they are not contrary to any laws of Judaism.

Unlike Anglo-American common law, though, Halakhah does not rely on a strict theory of binding precedent nor provide for systematic review of precedents. Generally, Halakhic arguments are effectively, yet unofficially, peer-reviewed. When a rabbinic posek'' ("decisor") proposes a new interpretation of a law, that interpretation may be considered binding for the posek's questioner or immediate community. Depending on the stature of the posek and the quality of the decision, an interpretation may also be gradually accepted by rabbis and members of similar Jewish communities.

Under this system, there is a tension between the relevance of earlier and later authorities in constraining halakhic interpretation and innovation. On the one hand, there is a principle in Halakha to not overrule a specific law from an earlier era, unless based on an earlier authority. On the other hand, another principle recognizes the responsibility and authority of later authorities, and especially the posek handling a concurrent question. In addition, the Halakha embodies a wide range of principles that permit judicial discretion and deviation (Ben-Menahem). Generally speaking, a rabbi in any one period will not overrule specific laws from an earlier era, unless supported by a relevant earlier precedent; see list below. There are important exceptions to this principle, which empower the posek (decisor) or beth din (court) responsible for a given opinion.

Notwithstanding the potential for innovation, rabbis and Jewish communities differ greatly on how they make changes in Halakha. Notably, poskim frequently extend the application of a law to new situations, but do not consider such applications as constituting a "vary" in Halakha. For example, many Orthodox rulings concerning electricity are derived from rulings concerning fire, due to its similarity with that other form of human-managed energy. Conservative Judaism and Reform Judaism tend to explicitly interpret Halakha to take into account sociological factors. For instance, the liberal Jewish movements extend the application of certain Jewish obligations and permissible activitites to women. See below: How Halakha is viewed today.

There is no formal peer-review process for the entire Jewish community in general, since the Jewish community has no one central body that speaks for all of Judaism. However, within certain Jewish communities formal organized bodies exist: Each division or dynasty of Orthodox Hasidic Judaism has their own rebbe, who is their ultimate decisor of Jewish law. Within Modern Orthodox Judaism, there is no one committee or leader, but Modern Orthodox rabbis generally agree with the views set by consensus by the leaders of the Rabbinical Council of America. Within Conservative Judaism, the Rabbinical Assembly has an official Committee on Jewish Law and Standards.

In antiquity, the Sanhedrin functioned essentially as the Supreme Court and legislature for Judaism, and had the power to create and administer binding law on all Jews - rulings of the Sanhedrin became Halakha; see Oral law. That court ceased to function in its full mode in CE 40. Today, application of Jewish law is left to the local rabbi, and the local rabbinical courts, with only local applicability.

Eras of history important in Jewish law
The Tannaim are the sages of the Mishna (70–200) The Amoraim are the sages of the Talmud (200–500) The Savoraim are the classical Persian rabbis (500–600) The Geonim are the rabbis of Sura and Pumbeditha, in Babylonia (650–1250) The Rishonim are the rabbis of the early medieval period (1250–1550) preceding the Shulkhan Arukh The Acharonim are the rabbis of 1550 to the present.

The thirteen rules by which Jewish law was derived
During the time of the Mishnah, the oral law was said to be derived from the written Torah by virtue of one or more of the following methods ("Introduction to Sifra" by Ishmael ben Elisha, c. 200 CE):

Scholars have noted the similarity between these rabbinic rules of interpretation and the hermeneutics of ancient Hellenistic culture.

How Halakha is viewed today
Orthodox Judaism holds that the words of the Torah (Pentateuch) were indeed dictated by God to Moses in almost precisely the way that they exist in the Torah today. The laws contained in the Written Torah were given along with detailed explanations as how to apply and interpret them, the Oral Law. The religious laws that Jews know today are thus directly derived from Sinai. As such, one must be extremely conservative changing or adapting Jewish law. Orthodox Judaism holds that, given Jewish law's Divine origin, no underlying principle may be compromised in accounting for changing political, social or economic conditions; in this sense, "creative thinking" and development in Jewish law is limited. See Orthodox beliefs about Jewish law and tradition.

To the Orthodox Jew, Halakha is a guide, God's Law, governing the structure of daily life from the moment he or she wakes up to the moment he goes to sleep. It includes codes of behavior applicable to a broad range of circumstances (and many hypothetical ones).

Conservative Judaism holds that the current text of the Torah is a composite that was redacted together from earlier sources. Conservative Jews hold that it is possible to believe that God is real and that prophets like Moses really were inspired by God. However, whatever records and traditions relating to such events were apparently transmitted in various forms for many centuries. This says nothing about whether the Torah is based on God or not, and so this idea not a theological threat. Therefore Conservative Judaism teaches that one should make use of literary and historical analysis to understand how these texts developed, and to help them understand how they may applied in our own day. Conservative Jews view the laws and customs from the various law codes as the basis for normative Jewish law. Solomon Schechter writes "however wonderful a literary value of a code can be, it doesn't invest it by using infallibility, nor even have sex exempt it from either either a student or a Rabbi world health organizatiin makes apply of it from the duty of examining from each one paragraph on its have merits, & subjecting it to the equivalent system of interpretation that were universally applied to Tradition". [Solomon Schechter].

Reform Judaism and Reconstructionist Judaism both hold that modern views of how the Torah and rabbinic law developed imply that the body of rabbinic Jewish law is no longer normative (seen as binding) on Jews today. Therefore Jews are not expected or taught to follow most of halakha. Those in the traditionalist wing of these movements hold that each Jew is obligated to interpret the Torah, Talmud and other Jewish works for themselves, and this interpretation will create separate commandments for each person. Those in the neo-traditional wing of Reform include Rabbis Eugene Borowitz and Gunther Plaut.

Those in the liberal and classical wings of Reform believe that in this day and era most Jewish religious rituals are no longer necessary, and many hold that following most Jewish laws is actually counter-productive. They propose that Judaism has entered a phase of ethical monotheism, and that the laws of Judaism are only remnants of an earlier stage of religious evolution, and need not be followed. This is considered wrong (and arguably heretical) not only by Orthodoxy, but by Conservative Judaism, and perhaps by some in the traditional wing of Reform.

Flexibility within the Halakha
Throughout history, halakha had been a remarkably flexible system, despite its internal rigidity, addressing issues on the basis of circumstance and precedent. For instance, rulings regarding modern technology have been incorporated into the ever-expanding halakhah. New rulings guide the observant about the proper use of electricity on the Sabbath and holidays within the parameters of halakhah. (Many scholarly tomes have been published and are constantly being reviewed ensuring the maximum coordination between electrical appliances and technology with the needs of the religiously observant Jew, with a great range of opinions.) Often, as to the applicability of the law in any given situation, the proviso is: "Consult your computers local Orthodox rabbi or even posek."

Modern critics, however, charge that with the rise of movements that challenge the "Divine" authority of halachah, traditional Jews have greater reluctance to change, not only the laws themselves but also other customs and habits.

As above, Orthodox Jews hold that, unlike secular precedent-based systems, halakha is a religious system, whose axiom is that Jewish law represents the will of God, either directly, or as close to directly as possible. If the laws in Jewish law codes are not the word of God per se, they are nonetheless derived from the literal word of God in the Torah, using a set of rules also revealed by God to Moses on Mount Sinai, and have been derived with the utmost accuracy and care. As such, one must be extremely conservative changing or adapting Jewish law. There have, nevertheless, been many changes including the application of halakha to modern technology.

The view held by Conservative Judaism (and to some extent within the left wing of Orthodoxy) is that while God is real for theological reasons, the Torah is not the word of God in a literal sense. However, in this view the Torah is still held as mankind's record of its understanding of God's revelation, and thus still has divine authority. In this view, traditional Jewish law is still seen as binding. Jews who hold by this view generally try to use modern methods of historical study to learn how Jewish law has changed over time, and are more willing to change Jewish law in the present.

Codes of Jewish law

The Torah and the Talmud are not formal codes of law; they are sources of law. There are many formal codes of Jewish law that have developed over the past few thousand years. The major codes are:

The Mishnah, composed by Rabbi Judah the Prince, in AD 200, as a basic outline of the state of the Oral Law in his time. This was the framework upon which the Talmud was based.

The Hilchot of the Rif, Rabbi Isaac Alfasi (1013–1103), summations of the legal material in the Talmud.

The Mishneh Torah (also known as the Yad Ha-Hazaqah), by Maimonides (Rabbi Moshe ben Maimon, the Rambam). The 14 volumes in this work encompass the full range of Jewish law, as formulated for all ages and places. It completely reorganizes and reformulates the laws in a logical system. It opens with a section on systematic philosophical theology, derived largely from Aristotelian science and metaphysics, which it regards as the most important component of Jewish law.

The work of the Rosh, Rabbi Asher ben Jehiel (1250?/1259?-1328), an abstract of the Talmud, concisely stating the final Halakhic decision and quoting later authorities, notably Alfasi, Maimonides, and the Tosafists. This work superseded Rabbi Alfasi's and has been printed with almost every subsequent edition of the Talmud.

The Sefer Mitzvot Gadol (The "SeMaG") of Rabbi Moses ben Jacob of Coucy (13th century, Coucy, France). "SeMaG" is organised around the 365 negative and the 248 positive commandments, separately discussing each of them according to the Talmud (in light of the commentaries of Rashi and the Tosafot) and the other codes existent at the time.

The Arba'ah Turim (The Tur, The Four Columns) by Rabbi Jacob ben Asher. (1270 - 1343, Toledo, Spain.) The Tur followed Maimonides's precedent in arranging his work in a topical order. However, the Tur covers only those areas of Jewish religious law that were in force in the author's time. The code is divided into four main sections; almost all Jewish codes of law since this time have followed the Tur's arrangement of material. Orach Chayim - "The Way of Life" worship and ritual observance in the home and synagogue, through the course of the day, the weekly sabbath and the festival cycle. Yoreh De'ah - "Teach Knowledge" assorted ritual prohibitions, dietary laws and regulations concerning menstrual impurity. Even Ha-'Ezer - "The Rock of the Helpmate" marriage, divorce and other issues in family law. Hoshen Mishpat - "A Egis of Judgment" The administration and adjudication of civil law.

The Beit Yosef, and the Shulkhan Arukh of Rabbi Yosef Karo (1488–1575). The Beit Yosef is a huge commentary on the Tur in which Rabbi Karo clarifies the opinions of rabbinic authorities who lived after the time of Rabbi Yaakov. The Shulkhan Arukh is a more concise collection of the Beit Yosef. (Literally translated, Shulkhan Arukh means "placed table".) In writing the Shulkhan Arukh, Rabbi Yosef followed the chapter divisions of the Tur. Sephardic Jews use the Shulkhan Arukh as the basis for their daily practice.

Rabbi Moshe Isserles (Kraków, Poland, 1525 to 1572) noted that the Shulkhan Arukh was based on the Sephardic tradition, and he created a series of glosses to be appended to the text of the Shulkhan Arukh for cases where Sephardi and Ashkenazi customs differed. The glosses are called Hamapah, the "Tablecloth" for the "Placed Table". His comments are now incorporated into the body of all printed editions of the Shulkhan Arukh; typeset in a different script. Isserles' Darkhei Moshe is similairly a commentary on the Tur and the Beit Yosef.

The Shulchan Aruch HaRav of Rabbi Shneiur Zalman of Liadi (c. 1800) was an attempt to recodify the law as it stood at that time, stating the decided halakha, as well as the underlying reasoning; unfortunately, most of the work was lost in a fire prior to publication. It is held in esteem by some Hasidim, and is quoted as authoratitive by many subsequent works.

"Layperson oriented" digests of Halakha: The Kitzur Shulkhan Arukh of Rabbi Shlomo Ganzfried (Hungary 1804 -1886), based on the very strict Hungarian customs of the 19th century, became immensely popular after its publication due to its simplicity. This work is not binding in the same way as the Mishneh Torah or the Shulkhan Arukh. It is still popular in Orthodox Judaism as a framework for study, if not always for practice. Chayei Adam and Chochmat Adam by Avraham Danzig (Poland, 1748-1820) are similar Ashkenazi works. The Ben Ish Chai by Yosef Chaim (Baghdad, 1832 - 1909) is a corresponding Sephardi work.

The Mishnah Berurah of Rabbi Yisroel Meir ha-Kohen, (the "Chofetz Chaim", Poland, 1838 - 1933) is a commentary on the "Orach Chayim" section of the Shulkhan Arukh, discussing the application of each Halakha in light of all subsequent Acharonic decisions. It has become the authoritative halakhic guide for much of Orthodox Ashkenazic Jewry in the postwar period, supplanting the more scholarly Arukh HaShulkhan of Rabbi Yechiel Michel Epstein. Kaf HaChaim on Orach Chayim and parts of Yoreh De'ah, by Yaakov Chaim Sofer (Baghdad and Jerusalem, 1870 - 1939) is similair in scope, authority and approach to the Mishnah Berurah.

"The Alternative To Jewish Religious Practice", by Rabbi Isaac Klein, with contributions from the Committee on Jewish Law and Standards of the Rabbinical Assembly. This work is based on the previous traditional law codes, but written from a Conservative Jewish point of view. It is not accepted among Orthodox Jews.