In the name of God, the Giver of gifts, the Beneficent,
Is the Quran the inerrant and original Word of God?
Did God Himself author such a book?
Before you make that decision, condifer this:
The Quran borrows many things from the Bible, the Haggadah, the Zohar, the Talmud, the Infancy Gospels, the Avesta, etc.
It might be in Arabic, but it's not from one single source.
http://www.geocities.com/spenta_mainyu/islam7.htm
This is a Zoroastrian site that really shows that the Quran borrowed things from many sources.
Here are just a few things from the site.
Harut and Marut (similar to several accounts in the Talmud, especially Midrash Yalkut. The origin of these angels is Zoroastrianism where they are called Haurvatat and Amerodad);
Paradise full of Huris (female angels - like the ‘paries’ in Zorastrianism). The words ‘huri’, ‘jinn/cin’, and ‘bihist’ (paradise / pairidaeze / pairidaeza / firdaws) are borrowed from Avesta or other Pahlavi sources;
Each prophet predicting the next prophet (concept is from the books called Desatir-i Asmani where each Zoroastrian prophet predicts the next one. The opening sentence of these books is “In the name of God, the Giver of gifts, the Beneficent” which is similar to the opening formula of the suras in Qoran “With the name of God the Merciful and Gracious”);
The concept of seven heavens and seven hells (originally from Sumer, Zoroastrianism, via the Jewish books Hagigah and Zohar);
God lifting up the Mount Sinai and holding it over the heads of the Jews as a threat for rejecting the law in Qoran 7:171 (from the 2nd century Jewish apocryphal book, The Abodah Sarah)
The Childhood of Jesus: in Qoran 3:49 Jesus speaks from the cradle and creates birds of clay which he then turnes to living birds (from Thomas the Israelite’s Gospel of the Infancy of Jesus); the Palm tree which provides relief for the pain of Mary after Jesus’s birth in Qoran 19:22-26 (from the Lost Books of the Bible); the story of the baby Jesus talking in Qoran 19:29-33 (from the Arabic apocryphal fable from Egypt named the first Gospel of the Infancy of Jesus Christ);
Qoran refers to priests competing as to who would raise Mary. They throw their rods into the river, only Zacharias’ rod floats [ from the History of our Holy Father the Aged, the Carpenter (Joseph), Arabic Apocryphal Book] ;
The angel Malik (Qoran 43:77) rules over Cehennam / Cehennem (the name is taken from Molech, the ruler of fire in pagan Palestine);
Could the Quran truly be the direct Word of God?
It contains many things that are not original, in fact many things seem to have been borrowed from apocryphal Jewish, Christian, and Zoroastrian books.