" The Quran is the "Word of God" to Islam. About 4/5 the length of the New Testament. Muslims believe the identical book is in Heaven and Allah sent the angel Gabriel to Mohammed to reveal his "Word". The Quran is divided into 114 chapters or Surahs. The Surahs are revelations given to Mohammed during his 23 years of "Prophethood" from 610 AD to 632 AD.
The Quran, composed during Mohammed's lifetime corresponds to the time and circumstances of his life. The Surahs or chapters can be divided into three time periods. The earliest Surahs are the shortest and known as Early Meccan, and date from 610 to 622 AD. Composed in Mecca, prior to Hejira where Mohammed fled to Medina in September 622 AD.
The Madinah Surahs were composed during the time Muslims controlled the city of Medina. They date from 622 to 630 AD. The doctrine of Jihad was introduced as war was waged against Mecca and its idol worshipers. Animosity toward the Jews and Christians increased as they rejected Mohammed as a prophet from God.
Late Mecca Surahs were between 630 and 632 AD. The last 2 years of Mohammed’s life after Mecca surrendered to his authority.
Surahs were at this time not collected in one book but were memorized and collected on various items. In the battle of Yamamah in 633 AD many of the Hafiz died. The Hafiz were Muslims who had committed much of the Quran to memory. With the urging of Umar, Zayd ibn Thabit, one of Mohammed most trusted secretaries was appointed to the task of collecting the Quran into one book. Still later after different versions of the quran began to appear Zayd was put in charge of collecting all the Qurans throughout the Muslim world and issuing an authorized copy in the place of ones collected.
The Quran makes the appeal to its beauty and consistency with previous scriptures as proof of its inspiration.