Generally, an oral law is a rule or custom that is passed down through oral tradition or communicated orally. In some circumstances, it is a habit or custom that is given legal prominence and weight. Other times, an oral law is an order or rule that is given orally and considered to be a legally valid law.
Many organizations, cultures, and religions maintain a system of oral laws. For an oral law to be considered binding, it first must be publicly known. Any alleged breach of the law must be evaluated by a judge, and if the law has been found to be been broken, it must be punished.
In many societies, oral traditions were the primary way of enforcing norms of behavior amongst an illiterate population. While these oral traditions may have been less specific than modern written laws, they were commonly accepted as a way to preserve customs and traditions. They also provided procedures for resolving disputes and conflicts between members of the societies.
An oral law should not always be considered the equivalent of a written law that has not been been recorded. In systems bound by oral law, the rules are not generally abstract codes meant to be interpreted for their legal meaning. Instead, they are specific to a social context and only meaningful in certain situations. Oftentimes, these oral laws are only part of the greater social rules, and legal rules are not considered superior to other ethical and religious rules.
Unlike in traditional written legal systems, oral laws are not necessarily applied by formal judges, or enacted by legislators. Oftentimes, the "judge" in such a scenario is an elder or respected member of the society who is vested with the power to interpret and apply laws in certain circumstances. Since laws are based on the customs and rites passed down through the generations, the changing of political powers and rulers does not have a large effect on the laws governing the people.
In Judaism, the oral law consists of the teachings that God gave to Moses at Mount Sinai along with the Torah, which is considered the written law. The oral law acts as a commentary to the Torah, explaining how the commandments are to be fulfilled. These rules were passed down orally through generations, and eventually recorded in the Mishnah and the Talmud.
The oral law is considered necessary in most sects of Judaism to explain inconsistencies or omissions in the Torah. The text of the Torah glosses over certain elements that would have been obvious to early Jewish communities, such as the rules regarding marriage. For a modern audience, the oral law is necessary to explain such issues. However, different sects of Judaism do not agree completely on the binding nature of the oral law.