The Koran never said the Bible is corrupted:
(1) The Bible and the Qur’an is one book
a. The 3 major books of acceptance
It is He who sent down to thee (step by step), in truth, Book, confirming confirming what went before it; and He sent down the Torah (of Moses) and the Gospel (of Jesus) (Sura 3:3)
b. These books are in fact one book
“If you Muhammad are in doubt regarding that which we have revealed to thee, ask those who read the book from before you” (Yunus 10:94).
c. The previous Revelations are simply portions of the Book
Hast thou not turned thy thought to those who have been given a portion of the Book? They are invited to the Book of Allah, to settle their dispute, but a party of them turn back and decline (Sura 3:23)
Amazingally the Muslim has to accept the Bible (Latin = book, in Arabic = Kitab) as one Book with the Koran; I think this presents some serious problems for the Muslim to solve.
(2) The Qur’an verifies and confirms the previous Books
The Qur’an confirms and testifies to the previous Scriptures, it does not correct them but provides a fuller explanation
This Qur’an is not such as can be produced by other than Allah; on contrary it is a confirmation of (revelations) that went before it, and a fuller explanation of the Book-wherein there is no doubt from the Lord of the Worlds (Sura 10:37).
Let the people of the Gospel judge by what Allah hath revealed therein. If any do fail to judge by what Allah hath revealed, they are those who rebel.
To thee We sent the Scripture in truth, confirming the Scripture that came before it, and guarding it in safety: so judge by what Allah hath revealed and follow not their vain desires, diverging from the truth that hath come to thee...(Sura 5:47-48)
(3) The previous Books support and confirm the Qur’an as a foundation
If thou wert in doubt as to what we have revealed unto thee, then ask those who have been reading the Book from before thee, the truth hath indeed come to thee from thy Lord: so be in no wise of those in doubt (Sura 10:94)
(4) The Christian’s and the Jew’s possessed the previous Books in Muhammed’s lifetime
a. The Jews possess the Torah in the time of Muhammed
“But why do they (the Jews) come to thee for decision, when they have the Torah in which is the command of God”. (Al-Ma’ida 5:46)
b. The Christians possess the Injil in the time of Muhammed
“And let the people of the Gospel judge by what God has revealed in it. If any fail to judge by what God has revealed, they are licentious”. (Al-Ma’ida 5:50)
c. The previous Books in the hands of the Jews and the Christians
“And I will write down my mercy for those who are righteous and give alms and who believe in our signs; who follow the apostle, the unlettered prophet, whom they find written in the Torah and the Gospel that is with them”. (Al-A‘raf 7:156-157)
(5) The Christian’s and the Jew’s read the previous Books in Muhammed’s lifetime
“The Jews say, ‘The Christians are not founded upon anything.’ And the Christians say, ‘The Jews are not founded upon anything.’ And yet they read the book”. (Al-Baqara 2:113)
...whom they find written in the Torah and the Gospel that is with them (Sura 7:156-157)
If you Muhammed are in doubt regarding that which we have revealed to thee, ask those who read the book from before you (Sura 10:94)
(6) The previous Books are a guidance and light in Muhammed’s lifetime
After them we sent forth Jesus, the son of Mary, confirming the Torah, already revealed, and gave him the Gospel, in which there is guidance and light, corrobarting what was revealed before it in the Torah a guide and an admonition to the rigtheous (Sura 5:46)
(7) Since the previous Books are a guidance and light the Christian is to judge from them
And let the people of the Gospel judge by what God has revealed in it. If any fail to judge by what God has revealed, they are licentious (Sura 5:47)
(8) The Jew’s and Christians are to live according to the previous Books
“Say, O people of the book! You are not founded on anything until you perform the Torah and the Gospel, and what was revealed to you from your Lord”. (Al-Ma’ida 5:68-71)
(9) The Muslim is to believe these previous revelations in Muhammeds lifetime
Be courteous when you argue with People of the Book (Christian and Jews) except with those among them who do evil. Say: “ We believe in that which is revealed to us (Koran) and which was revealed to you (Kitab=Bible). Our God and your God is one”. (29:46)
The Messenger believeth In what hath been revealed to him from his Lord, as do the men of faith, each one (of them) believeth in Allah, His angels, His books, and His messenger. “We make no distinction (they say) between one and another of his messengers.” And they say: “We hear, and we obey: (we seek) Thy forgivness, our Lord, and to Thee is the end of all journeys” (Sura 2:285)
O ye who believe! Believe in Allah and his Messenger, and the Scripture, which He sent to his messenger, and the Scripture which he sent to those before (him). Any who denieth Allah, His angels, His Books, His messengers, and the day of judgement, hath gone fare astray (Sura 4:136)
(10) Muhammed is to consult these previous Scriptures
“If you Muhammad are in doubt regarding that which we have revealed to thee, ask those who read the book from before you ”. (Yunus 10:94)
“The apostles We sent before you were but men whom we inspired with revelations and with Scriptures. Ask the People of the Book if you know not”. (16:43)
(11) The followers of Jesus overcame
“O ye who believe! Be ye helpers of God: as said Jesus the son of Mary to the disciples, ‘Who will be my helpers for God?’ The disciples said, ‘We are God’s helpers!’ Then a portion of the Children of Israel believed, and a portion disbelieved: but we gave power to those who believed against their enemies, and they became the ones that prevailed.” (Al-Saff 61:14)
(12) The various nations will be judged according to their own book
And thou wilt see every nation bowing knee: every nation will be called to its Record: “This day shall ye be recompensed for all that ye did” (Sura 45:28)
(13) Denying the previous Scriptures brings serious consequences
O ye who believe! Believe in Allah and his Messenger, and the Scripture which He sent to His Messenger, and the Scripture which He sent to those before (Him). Any who denieth Allah, His angels, His Books, His messengers, and the day of judgement, hath gone fare astray (Sura 4:136)
The Bottom line is: Christians are nowhere commanded in the Bible (the Word of God) to believe in the Koran. Muslims however, are to believe in the Kitab = the Bible (the Book) every bit of, as it was read and understood and believed upon by the Christians and Jews in Muhammad's era.
This rules out Bible corruption; in fact if the Bible is corrupted, then we may as well leave our religions, both Muslims and Christians, since the Koran being one with the Bible and testifying to its suppreme integrity drowns with it.
The real problem coming up is the fact that the Muslim has to believe the Bible otherwise he has left the Islamic faith and is no longer a Muslim.
However, if he does believe the Bible and its teaching, it is obvious that he cannot be a Muslim either, SO WHAT IS HE?