The true Muslim believes in all the scriptures and revelations of Allah. They were the guiding light which the Messengers [a] received to show their respective peoples the Right Path of Allah. In the Qur’an a special reference is made to the books of Prophet Ibrahim [a] (Abraham), Prophet Musa [a] (Moses), Prophet Dawud [a] (David) and Prophet ‘Isa [a] (Jesus). But long before the revelation of the Qur’an to Prophet Muhammad [s] some of those books and revelations had been lost or currupted, others forgotten, neglected, or concealed. The only authentic and complete book of Allah in existence today is the Qur’an In principle, the Muslim believes in the previous books and revelations. But where are their complete and original versions? They could be still at the bottom of the Dead Sea, and there may be more Scrolls to be discovered. Or perhaps more information about them will become available when the Christian and Jewish archaeologists reveal to the public the complete original findings of their continued excavations in the Holy Land. For the Muslim, there is no problem of that kind.
The Qur’an is in his hand complete and authentic. Nothing of it is missing and no more of it is expected. Its authenticity is beyond doubt, and no serious scholar or thinker has ventured to question its genuineness. The Qur’an was made so by Allah Who revealed it and made it incumbent upon Himself to protect it against interpolation and corruption of all kinds. Thus it is given to the Muslims as the standard or criterion by which all the other books are judged. So whatever agrees with the Qur’an is accepted as Divine truth, and whatever differs from the Qur’an is either rejected or suspended. Allah declares, “Verily We have, without doubt, revealed the Qur’an and We will assuredly guard it!”