That seems to be a popular question by many muslims who believe the bible is corrupt.
When exactly do you believe that the Bible was corrupted and by whom?
when Muhammad recited the Qur'an, he made clear statements which show that he did not believe that the Bible was corrupt at that time. The Qur'an calls on Christians to adhere to the Scriptures that they possessed. There are also verses in the Qur'an which state that John the Baptist and Jesus were taught the Torah by Allah. If this is the case, then the Torah was still intact (according to the Qur'an) during the first century. Add to this the fact that we have in our possession the Dead Sea Scrolls and the Septuagint which predate John and Jesus' birth by some 200 years. Thus it is easy to demonstrate (for anyone who is willing to examine the facts) that according to the Islamic worldview and the manuscript evidence, it is impossible for the Bible to have been corrupted. The logical questions go on and on here. See:
http://www.answering-islam.org/Bible/multi.htmlhttp://www.answering-islam.org/Bible/Text/wijngaards.htmlhttp://www.answering-islam.org/Bible/jrwhy.html