We can start with a little philosophy,
Here an Illustration: consider a 1 metre scale. If one have to say that 1 metre scale is corrupted or changed he would have to bring a true 1 metre scale. That person can’t bring a protractor and say that the scale is corrupted because the protractor and scale measures different quantities (Scale measures length and protractor measures angle).
Keeping this illustration in mind assume Bible in the place of that 1 metre scale. If one has to say that the Bible is corrupted that person has to bring out a true Bible which is not corrupted. That person can’t refer to scriptures of other religion to show that the Bible is corrupted. It will be only like bringing a protractor to prove that the scale is changed. He either has to bring a true Bible or he has to find faults in the Bible.
Now is it clear that, to say the Bible is corrupted or changed is philosophically wrong!
Even though this philosophical argument is air-tight, we can go to other arguments and evidences to support that the Bible is not corrupted or fabricated.
a. The Bible was compiled only after the 4th century and there was no central control over the Bible before the 4th century. Before 4th century the disciples used to write and spread the manuscripts everywhere over the Old World. If anyone wanted to change anything written in the Bible, they would have to first collect all the manuscripts in an area and publish a new one. May be someone (or a group of people) could change the manuscripts in an area but how would that person (Or that group) be able to collect all the manuscripts throughout the Roman Empire. It is not practically possible to collect all the manuscripts throughout the entire Roman Empire without the help of the Roman Government. Indeed in 4th century the control over the Bible was centralized. But we have more than 5400+ Greek manuscripts, 10,000+ Latin, Aramaic, Coptic manuscripts of the New Testament in the world. All of these manuscripts date before 4th century. The Old Testament manuscripts where highly preserved by the Jews in B.C. itself. Therefore the Bible can be easily reconstructed with 99.9 percent accuracy. (For a comparison, Caesar’s Gallic war has only 10 manuscripts)
b. If the Bible was changed or corrupted, by Jesus’ disciples. The disciples of Jesus would have recanted their testimony upon facing death. Many of Jesus’ disciples were martyrs for their faith. No one would die for something they themselves would have fabricated.
The evidences make it clear that the Bible has not been changed or corrupted. May be the saying, “the Bible is corrupted” came out only to ignore the truth in the Bible. But there is a question worth asking oneself, “Am I ready to believe the Bible if it is not corrupted or fabricated?”
• The Holy Bible, NIV
• Questions Intellectuals Ask About Christianity, Henry F. Schaefer III
• Why Jesus, Nabeel Qureshi, James Tour Audios