I want to know about the reliability of the Bible because many of my friends who are Muslims tell me that Jesus did not die on the cross nor was he risen. They tell me that this is not written 600 yrs later but from 2nd century or the end of 1st century itself by Gnostic gospels. How do I answer them? They also tell me that the Bible was corrupted for the following reasons. Mark’s gospel is beloved to be the earliest written gospel, but it only tells what the angels said, but Jesus meeting then was added later. They say that Jesus spoke in Mark 16:9, but the ancient manuscripts don’t have that part. Also, in John where Jesus forgives a women caught in adultery, it also says that ancient documents don’t have that part which leads to a serious doubt on such verses which were added later in the Bible but not present in ancient manuscripts. So how can we trust them? Do we have evidences to prove Jesus’ death on the cross that is accepted by every scholar and historian in the planet no matter which religion they belong to? When did the the ideas of Jesus not dying on the cross originate? Is it from the end of then 1st century or from 2nd century itself? Muslims also say that Koran was written 20yrs after Mohammed died but not a century later as we believe. If oral work is trusted in Bible, the same applies to Koran is what they say. So how do I answer all these attacks on the Bible? They say the idea it’s Simon or Judas who died in Jesus’ place and it is there in the Gnostic gospels itself which were at the end of 1st century or 2nd century, which is not too far. How can we trust them?
I have already answered the question about Mark 16 and John 8 for you. We have thousands and thousands of manuscripts of the Greek New Testament, which allows us to answer all of these questions with great reliability. This is not the case with the Qur’an. The Caliph Uthman had all of the Qur’ans burned about one hundred years after Muhammad died. Essentially, he eliminated all the evidence (or nearly all the evidence) for the various readings of the Qur’an, of which there were many. There is the Saan’a manuscript, which survived the destruction of all the Qur’ans by Uthman. It has major differences with the accepted Qur’an of Uthman. Here is the difference between Islam and Christianity. Muslims totally ignore any evidence from other manuscripts. They pretend that there are no textual errors. They literally completely ignore the contrary evidence, making our trust in the Qur’an much weaker than in the reliability of the Bible. Ignoring evidence does not make it go away, and it does not increase the reliability of one’s conclusions. Good luck getting any Muslim to talk about this evidence! They are likely to threaten your life if you do. When the Saan’a manuscript was discovered in Yemen, not a single Muslim would even study it because of fear of their life or of losing their job. It was left to Westerners to study it. Muslims actively cover up all contrary evidence to the claim that their Qur’an is perfect, which it is not. I have more on this topic here: Apologetics and Islam
On the other hand, Christians happily and publicly discuss the various readings in the different manuscripts. There is an entire science and there are dozens of top scholars who look at all the manuscripts. They give preference to the older ones for obvious reasons. It is because of all the research we do that we are able to reproduce a virtually exact copy of the original of the New Testament. That is why we know that the original of Mark most likely did not include what we call Mark 16:9-20. We have SO much evidence to support the Bible, making any charge of corruption extremely weak indeed. Yet, Muslims, despite the weakness of support for their own Qur’an, keep bringing up this false charge against the Bible. Why is that? Is it because they want to uncover the truth? Absolutely not!!! It is because they know that the Bible says things about Jesus which contradicts what their Qur’an says about Jesus. So, they must undermine the Bible. Christians do not need to undermine the Qur’an because everyone with common sense knows that the Bible is going to have a more accurate account of what Jesus said and did. These attacks are really just a diversion. Which is more believable: Mark or John or Muhammad on the life of Jesus? This is one of the easiest questions ever asked, but it makes our Muslim friends very uncomfortable. The Qur’an does not have evidence to support it such as fulfilled prophecy, verified public miracles, archaeological or historical accuracy, all of which the Bible has in great amount. So, they try to change the subject.
Remember, that Muslims require that the New Testament is so corrupt that the very accounts of the crucifixion of Jesus are invented and that the dozens of times he is claimed to be God are also corruptions. It is so obvious that this is not true, that you would think that they would stop making these charges. Yet they continue, because many of their hearers are ignorant of what the data says, which is that the New Testament in Greek is reliable to a greater than 99% decree of accuracy to the original. Muslims try to make us believe that it is totally corrupted. Not true!!!
Does every scholar and historian on the planet agree that Jesus was killed on the cross? Well, every serious scholar I have ever read has agreed with this. The Encylopedia Britannica says so. Every encyclopedia ever published says so. Every significant history book ever written says so. Ever ancient historian who talked about it (Eusebius, Tacitus, Josephus and more) also agree that he was crucified. Who does not agree? A false prophet writing more than six hundred years after the event (and also some heretical Christians in the late second century). Who should I believe? The people who lived with Jesus and who were at his crucifixion or a person living in Arabia six hundred years later? The answer is very obvious.
About the Qur’an, I believe that most of it was recited by Muhammad. It was passed along by memory for about one generation, and then written down about twenty years later. This is almost identical to the gospels. Mark was written between twenty and thirty years after Jesus died. I do not know who says the Qur’an was written one hundred years later. That is not true. What IS true, however, is that it was about 100 years later that Uthman tried to get all Qur’ans destroyed because there were so many different versions, and he wanted to create a single version. That is true. It is also why the Qur’an is relatively unreliable. It is my opinion that the Qur’an is fairly reliable as the words of Muhammad. It is perhaps even nearly as reliable as the New Testament, but the evidence is weaker, unfortunately. So, I agree with what your Muslim friends say about the Qur’an (that it was written more like 20 years, not 100 years later) because the evidence supports this. Unfortunately, they choose not to similarly believe the evidence for the New Testament because they are not comfortable with the obvious implications.
Where did the idea of Jesus not dying on the cross come from? Historically, it came from the Gnostics, who were heretics. It was in the second half of the second century when they falsely claimed that Jesus only appeared to have been killed on the cross. They did not claim that it was a mistaken identity. That idea originated with Muhammad. They claimed that he was a spiritual being who only occupied the body of the person we call Jesus. This is sometimes called Docetism. This is NOT what Muhammad claimed. His claim is that they crucified the wrong person. As far as I know, he invented this idea, but I cannot swear that no one said that earlier. I would not be surprised that pagan Greek enemies of the Church might have said that before Muhammad.
Either way, the fact that people falsely claim that Jesus was not crucified, does nothing to undo the clear evidence that he was in fact crucified, such as the eye-witnesses and all testimonies from the first century, including non-Christian writers.
You say that “they say it was Simon or Judas.” Who says this? When did they say this? I cannot respond to such a vague claim coming from an unknown person at an unknown time. The Gospel of Judas has Jesus saying to Judas that the Romans did him a favor by having him killed, because it freed him from his physical body. It does NOT say that it was Judas or Simon who was killed. We need to deal with the evidence, which is clear. Anyone can say anything they like, but we need to look at the evidence, which is very solid!