The best Christian defense is not silly: the Bible is supported by many manuscripts, early quotations, and a serious scholarly tradition of textual criticism. A Muslim answer should grant that strength, then ask the sharper question: does this prove that the present Bible is exactly the revelation Allah gave, and a final authority over the Quran?
How the Christian case is usually made
Christians often argue that the New Testament, especially, is better attested than most ancient books. There are thousands of Greek manuscripts, early translations, and quotations from early church writers. Even where manuscripts differ, they say textual critics can usually identify the earlier reading, and most variants do not affect central doctrine.
They also add a Quranic argument: the Quran speaks of the Torah and Gospel as revelation, "guidance and light," and addresses Jews and Christians as People of the Book. So, they argue, if the Bible was already corrupted before Islam, why would the Quran speak this way?
What the Quran actually affirms
The Quran does affirm that Allah revealed the Torah and the Gospel. Muslims do not believe Moses and Jesus, peace be upon them, came with falsehood. The issue is not whether revelation was sent; it is whether later communities preserved it fully and interpreted it faithfully.
And We gave him the Gospel, in which was guidance and light, and confirming that which preceded it of the Torah as guidance and instruction for the righteous.
Quran 5:46
But the same Quran also says that some among the People of the Book altered words, concealed truth, and attributed writings to God falsely.
So woe to those who write the Scripture 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 usages and have forgotten a portion of that of which they were reminded.
Quran 5:13
So the Quranic position is balanced: earlier revelation was real, traces of truth remain, but the Quran judges what is now in people's hands.
And We have sent down to you the Book in truth, confirming that which preceded it of the Scripture and as a criterion over it.
Quran 5:48
Textual preservation is not the whole question
The Christian manuscript argument mainly helps with one matter: it can show that much of the New Testament text known today is close to what Christians were reading in the early centuries. That is a serious historical point.
But it does not prove that every book is revelation from Allah, that the authors were prophets, that every theological interpretation is correct, or that no loss, selection, editing, or doctrinal development occurred before the surviving manuscript tradition became widespread.
For example, the Quranic "Injil" is the revelation given to Jesus, peace be upon him. The four canonical Gospels are later accounts about Jesus, written in Greek, not a book authored by Jesus himself. A Muslim can respect them as historically important without accepting them as identical to the Injil revealed by Allah.
What this argument does and does not establish
The strong Christian case establishes that the Bible cannot be dismissed as a late medieval fabrication. It contains ancient material, preserves many teachings near to early Jewish and Christian communities, and includes moral and spiritual truths Muslims can recognize.
It does not establish that the Bible is perfectly preserved revelation, that the Quran is wrong about distortion and concealment, or that doctrines such as the Trinity, original sin, or the crucifixion as atoning redemption must be accepted over the Quran.
So the fair Muslim answer is not, "The whole Bible is fake." It is: Allah sent true revelation before, people preserved some of it and mishandled some of it, and the Quran came as the final criterion. That position is historically modest, Quranically grounded, and intellectually coherent.