Muslims believe the Quran to be God's final revelation to humanity, a work of divine guidance revealed to Muhammad through the angel Gabriel. Revered by pious Muslims as "the holy of holies," whose sound moves some to "tears and ecstasy", it is the physical symbol of the faith, the text often used as a charm on occasions of birth, death, marriage. Consequently, It must never rest beneath other books, but always on top of them, one must never drink or smoke when it is being read aloud, and it must be listened to in silence. It is a talisman against disease and disaster.Ibn Warraq, Why I'm Not a Muslim, 1995: p.105 Traditionally great emphasis was put on children memorizing the 6,200+ verses of the Quran, those succeeding being honored with the title Hafiz. "Millions and millions" of Muslims "refer to the Koran daily to explain their actions and to justify their aspirations," and in recent years many consider it the source of scientific knowledge. Revelation in Islamic and Quranic contexts means the act of God addressing an individual, conveying a message for a greater number of recipients. The process by which the divine message comes to the heart of a messenger of God is tanzil ('to send down') or ('to come down'). As the Quran says, "With the truth we (God) have sent it down and with the truth it has come down." The Quran frequently asserts in its text that it is divinely ordained. Some verses in the Quran seem to imply that even those who do not speak Arabic would understand the Quran if it were recited to them. The Quran refers to a written pre-text, "the preserved tablet," that records God's speech even before it was sent down. Muslims believe that the present wording of the Quran corresponds to that revealed to Muhammad, and according to their interpretation of Quran , it is protected from corruption ("Indeed, it is We who sent down the Quran and indeed, We will be its guardian."). Muslims consider the Quran to be a guide, a sign of the prophethood of Muhammad and the truth of the religion. The Shīa believe that the Quran was gathered and compiled by Muhammad during his lifetime, rather than being compiled by Uthman ibn Affan. There are other differences in the way Shias interpret the text. Muslims do not agree over whether the Quran was created