The Noahide Laws
Seven commandments which, according to Jewish tradition, are incumbent upon all of humankind.
"God speaks to Noah and his children as they exit the ark: 'Behold, I establish my covenant with you, and with your seed after you' (Genesis 9:9)."
Although rabbinic texts preserve various traditions about the details of this covenant, the Talmud reports the following:
"The children of Noah were commanded with seven commandments: [to establish] laws, and [to prohibit] cursing God, idolatry, illicit sexuality, bloodshed, robbery, and eating flesh from a living animal (Sanhedrin 56a; cf. Tosefta Avodah Zarah 8:4 and Genesis Rabbah 34:8)."
The prohibition against idolatry refers specifically to idolatrous worship, and not to beliefs. In later generations, Jews had to determine whether the prevailing religious cultures in which they lived were idolatrous. Since Islam is strictly monotheistic, Muslims have always been considered Noahides. Since the later Middle Ages, Jews have acknowledged that the Christian doctrine of the Trinity was not the same as idolatry, and they were also recognized as Noahides.
The prohibition against theft includes kidnapping, cheating an employee or an employer, and a variety of similar acts.
The prohibition against illicit sexuality includes six particular prohibitions, derived from a single verse:
"Noahides are prohibited from engaging in six illicit sexual relationships: with one's mother, with one's father's wife, with another man's wife, with his sister from the same mother, in a male homosexual union, and with an animal as it says, 'Therefore shall a man leave his father…' this refers to his father's wife; 'and his mother…" refers to the mother; 'and cling to his wife…' and not another's wife; 'wife…' and not a homosexual union; 'and become one flesh' (Genesis 2:24) excluding animals…" (Maimonides, Laws of Kings, 9:5).
Eating flesh from a living animal is how the rabbis understood "But flesh with its life, which is its blood, you shall not eat" (Genesis 9:4). It has been suggested that the custom of eating an amputated limb of an animal was a way to keep the rest of the meat fresh in the days before refrigeration.
The Obligation to Create a System of Laws
According to the medieval philosopher and codifier Maimonides, the legal system which Noahides are required to set up is specifically to establish punishments for infractions of the other six Noahide laws (Laws of Kings 9:14).
Nahmanides, a medieval Bible commentator, understands the obligation more broadly:
"In my opinion, the laws which the Noahides were to establish according to their seven commandments is not only to establish courts in each town, but that they were also commanded concerning theft, abuse, usury, labor relations, damages, loans, business, and the like, just as Israel was commanded to set up laws in these matters (Nahmanides, Commentary to Genesis 34:13)."