Definition of religious law
In some religions, law can be thought of as the ordering principle of reality; knowledge as revealed by a God defining and governing all human affairs. Law, in the religious sense, also includes codes of ethics and morality which are upheld and required by the God. Examples include customary Halakha (Jewish law) and Hindu law, and to an extent, Sharia (Islamic law) and Canon law (Christian law).
Sharia and Canon law differ from other religious laws in that Canon law is the codification of Catholic, Anglican and Orthodox law (like in a civil law tradition), while Sharia law derives many of its laws from juristic precedent and reasoning by analogy (like in a common law tradition).
Established religions and religious institutions
A state religion (or established church) is religious body or creed officially endorsed by the state. In some jurisdictions, this means that they operate legal systems of their own or play a part in the legal system of those governments. Canon law is one such sort of legal system; it was administered in ecclesiastical courts. A theocracy is a form of government in which a God or a deity is recognized as the supreme civil ruler.
The opposite are secular states, in which there is a separation of church and state.
Source: Wiktionary. Published under the Creative Commons Attribution/Share-Alike License.