The Qur'an or the Koran or the Qoran (Arabic: القرآن, al-Qurʾān) is the holy book for believers of Islam (English translation). Muslims believe the book was delivered bit by bit to the Prophet Muhammad, by the Angel Jibril (Gabriel, in Judaism and Christianity), and that it contains the words of God. The Qurʾān is divided into 114 Suras (chapters), each of them traditionally divided into verses called Ayah (Arabic for sign). There are a total of 6236 Ayah in one standard edition of the Qur'an. Others divide the text slightly differently.
There are two types of Suras: ones that were given in Mecca, before Muhammad made the Hijra to Medina. These Suras are more general, and often contain encouraging words for the Prophet and his believers, due to the persecution he suffered from the pagans. The Suras from Medina are more specific, and contain instruction and laws. The Islamic Sharia is based on these verses.
Suras are not organized by the order they were revealed to Muhammad, rather they appear in the book according to their length. Starting from the longer ones, with few exceptions.
During the middle ages of Islam, many theological debates revolved around the Qurʾān. The Mu'tazilah school, affected by Greek philosophy and rationalism, considered the Qurʾān to be created by God, therefore not eternal. The more conservative schools viewed the Mu'tazili position as blasphemy, and argued that the Qurʾān is the word of God, a part of God, and therefore was not created, but always existed.