In Islamic usage, "corruption" of earlier religious texts does not mean that every line is false. It means that the original revelation was not preserved with the same guaranteed protection as the Quran, and that truth became mixed with alteration, concealment, misreading, and human authorship.
The strongest form of the objection
The objection is fair when stated carefully. A critic may say: Muslims often claim the Bible is "corrupted" whenever it disagrees with the Quran, but the Quran itself speaks respectfully of the Torah and Gospel as guidance and light. It even addresses the People of the Book as people who possess scripture. So, the critic argues, "corruption" in the Quran may only mean bad interpretation or dishonest use, not a changed text. If so, Muslims cannot simply dismiss biblical passages that conflict with Islam.
What the Quran actually accuses people of
The Quran's language is broader than one single kind of corruption. It mentions distortion of meaning, concealment, selective quotation, forgetting part of the message, and also writing something and presenting it as divine.
Do you hope that they will believe you while a party of them used to hear the words of Allah and then distort it after they had understood it, while they were knowing?
Quran 2:75
So woe to those who write the Book with their own hands, then say, "This is from Allah," in order to exchange it for a small price.
Quran 2:79
They distort words from their places and have forgotten a portion of that of which they were reminded.
Quran 5:13
These verses are not all saying the same thing. Some describe twisting the meaning. Some describe hiding what was revealed. Some describe textual or scribal corruption. The classical Muslim view allowed for all of these, while also recognizing that much truth remained in earlier scriptures.
Affirming origin is not the same as affirming preservation
Islam teaches that the Torah and Gospel, as originally revealed, were from Allah. That is why the Quran can praise them as guidance and light. But it also says the Quran came as a guardian and criterion over previous scripture:
And We revealed to you the Book in truth, confirming what came before it of the Scripture and as a guardian over it.
Quran 5:48
This is the key distinction. The Quran confirms the divine origin of earlier revelation, not the perfect preservation of every later manuscript, translation, interpretation, or theological claim attached to it. So when a previous text agrees with the Quran, Muslims may accept it as part of the remaining truth. When it contradicts the Quran, Muslims do not treat it as binding revelation.
The Prophet (PBUH) taught this balanced approach:
Do not believe the People of the Book and do not disbelieve them, but say, "We believe in Allah and what has been revealed to us and what has been revealed to you."
Sahih al-Bukhari
What this does and does not prove
It does establish the Islamic position: previous revelations were real, but their later transmission was not protected in the way the Quran was protected. "Corruption" includes more than mistranslation or bad commentary; it can include changes in wording and attribution.
It does not establish that every biblical sentence is false, or that Jews and Christians are being accused as individuals of dishonesty. It also does not, by itself, convince someone who rejects the Quran's authority. For such a person, the discussion must also include manuscript history, authorship, canon formation, and theology.
So the Muslim claim is more precise than a slogan. The earlier scriptures contain truth, but they are not the final measure of truth. The Quran is.