Examples of legal systems derived from religion include Jewish halacha, Islamic Sharia, Christian canon law (applicable in a broader theological conception in the church, but separate from secular state law in modern times, and Hindu law.  But to truly participate, we need to know our rights – otherwise we may lose them. The supreme law of our land is the Constitution of the United States, which contains certain amendments known as the Bill of Rights. The Bill of Rights guarantees that the government can never deprive the people of the United States of certain fundamental rights, including the right to freedom of religion and expression and due process. Many federal and state laws also grant us additional rights. While some government measures involving religion are permissible and even inevitable, it is not clear to what extent the establishment clause tolerates. In the past, the Supreme Court has allowed religious invocations to open legislatures, public funds for private religious school buses and textbooks, and university funds for printing and publishing publications by religious student groups. Conversely, the court ruled against certain overtly religious manifestations in courthouses, public funds intended to supplement teachers` salaries in religious schools, and certain decorations of excessively religious holidays on public land. In some Christian denominations, the law is often opposed to grace (see also Law and Gospel and Antithesis of the Law): the contrast here speaks of an attempt to obtain salvation through obedience to a code of law, as opposed to seeking salvation through faith in the Atonement Jesus made on the cross. From the Gospel of John: The Greek-speaking Orthodox collected canons and commentaries about them in a work known as the Pēdálion (Greek: Πηδάλιον, “oar”), so called because he is supposed to “lead” the Church. The Orthodox Christian tradition generally treats its canons as guidelines rather than laws, with bishops adapting them to cultural and local circumstances. Some Orthodox canonical scholars point out that if the ecumenical councils (which deliberated in Greek) had used the canons as laws, they would have called them nómoi / νόμοι (laws) instead of kanónes / κανόνες (rules), but almost all Orthodox conform to them.
However, the dogmatic decisions of the Councils must be followed rather than dealt with, for they are essential for the unity of the Church. In Presbyterian and Reformed churches, canon law is known as “practice and procedure” or “order of the church” and includes the laws of the church that respect its government, discipline, legal practice, and worship. Positive ecclesiastical laws derive formal authority in the case of universal laws from promulgation by the supreme legislator – the pope – who has all legislative, executive and judicial power in his person, while some laws derive formal authority from promulgation by a legislator inferior to the supreme legislator, whether ordinary or delegated. The real subject of the canons is not only doctrinal or moral in nature, but encompasses everything of the human condition. Think of your friends who have a different faith or no religious belief at all. They would always feel excluded from their own final exercises. Or worse, they would feel that the school thought your religion was better than theirs. Place the shoe on the other foot for a second and think about how you would feel! In theocracies and some religious jurisdictions, conscientious objectors may provoke religious insults. The opposing legal systems are secular states or multicultural societies in which the government does not formally adopt a particular religion, but can either suppress all religious activities or impose tolerance of religious diversity.
Sharia, also known as Islamic law (قانون إسلامي qānūn ʾIslāmī), is the moral code and religious law of Islam. Sharia is derived from two main sources, the commandments of the Qur`an and the example of the Islamic prophet Muhammad in the Sunnah. Islamic jurisprudence (fiqh) interprets and extends the application of Sharia law to issues that are not directly addressed in primary sources by including secondary sources. These secondary sources usually include the consensus of ulema (religious scholars) embodied in Ijma, and analogies from the Qur`an and Sunnah by Qiyas. Shia jurists prefer to use arguments (`aql) rather than analogies to answer difficult questions. [ref. needed] A state religion (or established church) is a religious body officially supported by the state. A theocracy is a form of government in which a god or deity is recognized as the supreme civil ruler. In the Church of England, ecclesiastical courts, which adjudicated many matters such as disputes relating to marriage, divorce, wills and defamation, still have jurisdiction over certain ecclesiastical matters (e.g. discipline of clergy, alteration of church property, and matters relating to cemeteries). Its distinct status dates back to the 11th century, when the Normans separated it from the mixed secular/religious county and local courts of the Saxons. Unlike other courts in England, the law used in ecclesiastical matters is, at least in part, a civil law system, not a common law system, although it is heavily regulated by parliamentary acts.
Since the Reformation, ecclesiastical courts in England have been royal courts. The teaching of canon law at the universities of Oxford and Cambridge was initiated by Henry VIII. Repealed; Subsequently, practitioners were trained in civil law in ecclesiastical courts and received a Doctor of Civil Law (D.C.L.) from Oxford or an LL.D. from Cambridge. These lawyers (called “doctors” and “civilians”) were centered in “Doctors Commons”, a few blocks south of St Paul`s Cathedral in London, where they monopolized probate, marriage and admiralty cases until their jurisdiction was transferred to the common law courts in the mid-19th century. Those who are versed and qualified in canon law, and professors of canon law, are called canonists (or colloquially canon lawyers).  Canon law as a sacred science is called canonical studies. The canon law of the Catholic Church (Latin: ius canonicum) is the system of laws and legal principles created and applied by the hierarchical authorities of the Church to regulate its external organization and government and to direct the activities of Catholics towards the mission of the Church.  It was the first modern Western legal system and it is the oldest permanently functioning legal system in the West, which preceded the European common law and civil law traditions. This began with rules (“canons”) established by the apostles at the Council of Jerusalem in the 1st century.
It has evolved into a very complex and original legal system that includes not only New Testament norms, but also elements of the Hebrew (Old Testament), Roman, Visigoth, Saxon and Celtic legal traditions spanning thousands of years of human experience.