The Quran is given as the book (kitab) to the Jews and Christians together and they read the same thing. Yet, the Quran is also the Book (kitab) given to the Arabian people. So, either the Quran thinks the Injil and the Torah are the same book given to different people and the Quran is the same as them just given to the Arabian people (which shows the Quran is false) OR the book that the Jews and Christians read is the bible at large and the Quran thinks the Jews read the NT.
The Qur’an speaks of “the Book” (al-Kitab) given to Jews and Christians together and implies they read the same “Book” (e.g., People of the Book, those who “recite the Book,” those given “the Book” before you).
Surah 2:113 explicitly states that Jews and Christians both "recite the Book" (yatluna al-kitaba) while arguing with each other. "The Book" here cannot be an abstract heavenly concept because they are "reciting" it on earth. If they are reciting the same object, the Quran is blind to the fact that their liturgies—the actual words being "recited"—are fundamentally different and mutually exclusive.
The Qur’an also calls itself “the Book” sent down to Muhammad and the Arabs (e.g., “This is the Book…”). The Quran doesn't just call itself "a book"; it claims to be the Arabic version of the same book already in their hands (Surah 46:12). This implies a 1-to-1 correspondence. If Al-Kitab is a singular genus, then the Quran is claiming to be the latest edition of the exact same manual.
Historically, there is no single physical/book-level scripture that Jews and Christians both accept as the same “Book”:
Jews accept the Tanakh, reject the Injil/NT.
Christians accept OT + NT; their “Book” is not the same as the Jewish one.
By the 7th century, the Jewish Tanakh and the Christian Bible were locked. Note that for a Jew, adding the Injil to "The Book" is not a minor update—it is an act of apostasy. The Quran addresses them as if they share a common library, ignoring the 500-year-old wall between the two communities regarding what constitutes "The Book."
So either the Qur’an is treating Torah, Injil, and Qur’an as essentially the same Book given to different peoples, or it is treating the Bible as a single Book that both Jews and Christians read in common (which would imply Jews read the Injil/NT).
Is it Essentialism (same message) or Materialism (same physical object). If it’s Essentialism, God is a poor communicator (since the messages contradict). If it’s Materialism, the Quran is historically illiterate (since the Jews never held the NT).
In either case, the Qur’an’s representation of “the Book” does not match historical reality, which undermines its claim to be a precise, divine description of previous scripture.
A "Clear Book" should not use a singular term (Al-Kitab) to describe three distinct, conflicting, and historically separated bodies of literature. The confusion is not in the reader; it is inherent in the text's terminology.
Take al-Kitab as the same underlying Book repeatedly given in different forms: Torah, Injil, and then Qur’an are essentially the same heavenly Book to different communities.
Then, in effect, the Qur’an is saying it is the same Book the Jews and Christians had, just in Arabic form.
But the actual contents and doctrines of the Torah, Gospel, and Qur’an contradict each other (on God, Messiah, crucifixion, salvation, etc.).
A single divine “Book” cannot simultaneously teach mutually exclusive doctrines. If the Injil says Christ was crucified and the Quran (4:157) says he wasn't, they cannot be the "same Book" in different languages. Islam has to admit that either the Injil was totally lost (which contradicts the Quran's command to judge by it) or the Quran is wrong.
Result: Either that “one Book” isn’t really one coherent revelation, or the Qur’an is wrong to identify itself with what Jews and Christians had. Either way, it fails.
Take al-Kitab as the Bible at large that “People of the Book” read.
Then the Qur’an is effectively saying Jews and Christians share one scripture (“the Book”) as a common object.
In reality, Jews do not accept or read the Injil/NT as scripture; they reject that part of the Christian Bible. The Quran tells Jews to look at the "Torah and the Gospel" (5:68).
So the Qur’an is factually wrong about what Jews actually read and recognize as “the Book.” To the Jew, the Gospel is not their "Book." By telling them it is, the Quran demonstrates a lack of "Inside Information" regarding the very people it seeks to convert.
Result: The Qur’an misidentifies the nature of Jewish and Christian scripture, which is not something an all-knowing God gets wrong.
So either “the Book” is one alleged revelation whose parts contradict each other, or the Qur’an is simply mistaken about what Jews and Christians read. Both options undermine its claim to be flawless revelation.
This Quranic "Book" is a literary fiction that exists only within the Quran itself. It describes a world where Jews and Christians share a scripture—a world that has never existed in history.