The Quran ( ; , , literally meaning “the recitation”; also romanised Qurʾan or Koran) is the central religious text of Islam, which Muslims believe to be a revelation from God (, Allah). Its scriptural status among a world-spanning religious community, and its major place within world literature generally, has led to a great deal of secondary literature on the Quran. Quranic chapters are called suras and verses are called ayahs. Muslims believe the Quran was verbally revealed by God to Muhammad through the angel Gabriel (Jibril), gradually over a period of approximately 23 years, beginning on 22 December 609 CE, when Muhammad was 40, and concluding in 632 CE, the year of his death. Muslims regard the Quran as the most important miracle of Muhammad, a proof of his prophethood, and the culmination of a series of divine messages that started with the messages revealed to Adam and ended with Muhammad. They consider the Quran to be the only revealed book that has been protected by God from distortion or corruption. According to the traditional narrative, several companions of Muhammad served as scribes and were responsible for writing down the revelations. Shortly after Muhammad’s death, the Quran was compiled by his companions who wrote down and memorized parts of it. These codices had differences that motivated the Caliph Uthman to establish a standard version now known as Uthman’s codex, which is generally considered the archetype of the Quran we have today. However, the existence of variant readings, with mostly minor and some significant variations, and the early unvocalized Arabic script mean the relationship between Uthman’s codex to both the text of today’s Quran and to the revelations of Muhammad’s time is still unclear. The Quran assumes familiarity with major narratives recounted in the Jewish and Christian scriptures. It summarizes some, dwells at length on others and, in some cases, presents alternative accounts and interpretations of events. The Quran describes itself as a book of guidance. It sometimes offers detailed accounts of specific historical events, and it often emphasizes the moral significance of an event over its narrative sequence. The Quran is used along with the hadith to interpret sharia law. During prayers, the Quran is recited only in Arabic. Someone who has memorized the entire Quran is called a hafiz. Some Muslims read Quranic ayahs (verses) with elocution, which is often called tajwid. During the month of Ramadan, Muslims typically complete the recitation of the whole Quran during tarawih prayers. In order to extrapolate the meaning of a particular Quranic verse, most Muslims rely on the tafsir.