The Quran is the sacred scripture of Muslims and is considered by them to embody the very word of God. According to orthodox Islamic teaching, the Quran is uncreated, meaning it is not made; based on this reasoning, it preexisted the creation of the world, residing in tablets near God, parts of which were sent down through the apostles (rasul) at extraordinary intervals to humanity. In this way, the initially sent message to the predecessors was completed with new parts from the tablets, unknown until then to humans. Thus, each new apostle added new teachings to the initially heaven-sent message during the evolutionary phase of the promise, until the full content of God's message was known to humans through Muhammad, who delivered it in its entirety, for which he was considered the last of the apostles and the pinnacle of the prophets.
The Quran as a sacred scripture contains everything concerning the world according to it; "We have omitted nothing from this book." Thus, it includes issues of cosmology, worship, regulation of human relations, criminal provisions, sanctions, etc. However, the Quran usually sets out the general principles or guidelines which are subsequently specified and detailed by the prophet's practice (Sunnah). Therefore, of the many thousands of verses it contains, only about two hundred refer to rules of law, and of these, following the process of abrogation (naskh), only eighty remain in force. [...]
(excerpt from the introduction by Kyriakos Th. Nikolaou-Patragas)