This verse provides a sharp historical snapshot of what Muhammad claimed to be doing: not replacing a lost book, but verifying a present one - the Torah.
Surah 2:101:
"And when there cometh unto them a messenger from Allah, confirming that which they possess, a party of those who have received the Scripture fling the Scripture of Allah behind their backs as if they knew not."
The Quran refers to the book in the hands of the Jews as the "Scripture of Allah" (Kitaba Allahi).
The Quran does not call it "the remnants of a corrupted book" or "the changed words of men." It calls the 7th-century Torah the "Scripture of Allah".
If it was the Scripture of Allah in the 7th century, then the Quran is confirming a book that contains the specific prophecies and laws of the Old Testament—laws that include the necessity of blood atonement and the specific lineage of the Messiah through Isaac, not Ishmael.
The verse rebukes the Jews for "flinging the Scripture... behind their backs."
A person only "flings away" or ignores something that is actually in their hands. You cannot fling away a book that was corrupted or lost 500 years prior.
The Quran blames the Jews for ignoring the truth contained in their own book. This implies the truth was present, readable, and clear. If the Jews had followed the "Scripture of Allah" they possessed, they would have seen the "confirmation." However, if a Jew follows the Torah, he must reject Muhammad (as the Torah warns against prophets who change the Law). The Quran is essentially blaming them for not seeing a "confirmation" that isn't actually there.
Muslim apologists often claim the Torah (and Bible) was corrupted early on (e.g., during the Babylonian exile or the 4th century).
Surah 2:101 destroys this timeline. If the book "with them" in the 7th century was already a corrupted mess, why does the Quran call it the "Scripture of Allah"?
This forces the corruption of the Torah to have happened AFTER Muhammad. But we have manuscripts (like the Aleppo Codex) from shortly after this period that match our modern Bibles. This leaves no room in history for the "corruption" to have taken place.
Using the"Character of God" argument:
In Surah 2:101, Allah calls the book held by the Jews 'The Scripture of Allah.'
If that book was corrupted, why is Allah calling a lie 'His Scripture'?
If that book was the Truth, then why does the Quran contradict it?
The Quran claims to confirm what they 'possess.' We know what they possessed—the Torah. If the Quran confirms the Torah, it confirms the very book that makes Islam unnecessary. If it doesn't confirm the Torah, then the Quran is false for claiming that it does."
This verse is particularly effective because it uses the Quran's own words (Kitaba Allahi) to grant the highest possible status to the 7th-century CE - Torah and Bible containing it.