Two accusations by skeptics regarding the Christian faith are that the miraculous aspects of the life of Jesus were invented late and that the written accounts we now have in the Bible were also written later than the lifetimes of the supposed authors. It is reasonable to conclude that neither of these accusations are true. The theology that Jesus died for our sins and then rose from the dead is present in the Christian community within 4 years and written down within 17 years of the death of Jesus. Starting with two epistles written by Paul we can date the doctrine of the resurrection to very soon after of the crucifixion of Jesus. It is the overwhelming conclusion by ancient historians – even Christian skeptics - that Paul did actually write these letters. 1st Corinthians was written by Paul around 53 AD, while Galatians was written sometime before 57 AD. The dating of Jesus’s death is debated, but it is either 30 AD or 33 AD. Using Paul’s writings, the logic goes as follows:
1. We know from many sources that Paul dies around 65 AD, 32-35 years after the crucifixion (yac)
2. 1st Corinthians was written around 53 AD, 20-23 years yac.
3. Paul went to Corinth around 51 AD (18-21 yac) and wrote down what he was taught. “that Christ died for our sins in accordance with the Scriptures, and that he appeared to Cephas and then to the twelve.”
4. Galatians records that when Paul became transformed, he went first to Arabia, then 3 years later went to Jerusalem to see Cephas and James. He then goes back to Jerusalem 14 years later. 51-14 = 37 AD (4-7 yac) when Paul first went to the apostles and “received” the ancient creed.
5. Paul went to Arabia for three years right after his conversion. 37-3 = 34 AD (1-3 yac).
In about 34 AD there was already a robust doctrine of the resurrection. This could be as early as 1 year after the crucifixion but no later than 3 years after. Remember, some time had to elapse between the crucifixion and Paul’s conversion because Christians had to become problematic enough for the Jewish leaders (Saul) to track them down and kill them! It is clear from uncontested letters written by an eye-witness that resurrection theology was present immediately after Jesus died.
What about the written documents? As mentioned above, we know for sure that Paul wrote down a Christian creed in about 50 AD, so written documentation of Christian Theology was surely present within 20 years after the death of Jesus. This is still well within the lifetimes of the eye-witnesses. As it turns out, it is reasonable to think that it was written down by others at an even earlier time. (The following argument comes from J. Warner Wallace in Cold Case Christianity)
1. Nowhere in the New Testament (NT) is there any mention of the destruction of the temple in 70 AD. If you were writing the history of New York City would you leave out the 9/11 attack on the Twin Towers? You would if you were writing the history before September 2001! This is the only explanation that makes sense; the destruction of the Jerusalem temple in 70 AD is one of the most significant historical events in the first century! Also, Jesus predicted it would happen! If the gospel were invented later, why write that Jesus predicted the destruction of the temple and then not mention that it actually happened! Conclusion: All NT documents were written prior to 70 AD.
2. NT does not mention the siege of Jerusalem at all. The city of Jerusalem was under assault for three years prior to the temple being destroyed; this is also a significant historical event for the writers of the NT. Suffering and persecution are common themes in the NT writings, so why leave out a significant time of suffering and persecution? Conclusion: All NT documents were written before 67 AD.
3. Luke does not mention the death of Paul, martyred in 62 AD, or the death of Peter, martyred in 65 AD. Paul and Peter are the two most prominent figures in the book of Acts; it would make no sense to leave out their deaths unless, of course, they weren’t dead yet! In fact, the book of Acts end with Paul under house arrest in Rome. Conclusion: All NT documents were written before 62 AD.
4. Luke does not mention the death of James (brother of Jesus) martyred in 62 AD. Luke describes the deaths of Stephen and James (brother of John), so why leave out the killing of the brother of Jesus?
5. According to Luke himself, Luke wrote his gospel before he wrote Acts. Conclusion: Luke’s gospel was written at least a few years before 62 AD.
6. Paul quoted Luke’s gospel in his first letter to Timothy, written in 62 or 63 AD. Paul wrote this as though Luke’s gospel was common knowledge and even referred to it as “Scripture.”
7. Paul summarizes the gospel message in his letter to the Corinthians, written about 50 AD.
8. Paul mentions “Scripture” and quotes Luke’s gospel in his letter to the Corinthians, written about 50 AD. Conclusion: Luke’s gospel was written, circulated, well-known and accepted as scripture by 50 AD. To be fair, let’s say it only took two years for Luke to write his gospel, have it circulated, and accepted as “Scripture.” This puts the writing of Luke’s gospel at 48 AD.
9. Luke quoted Mark and Matthew repeatedly. 350 verses from Mark appear in Luke’s gospel, while 250 verses from Matthew appear in Luke’s account. Conclusion: Matthew and Mark were both written, circulated, and well-known much earlier than 48 AD. We will use the same two years to provide enough time for Matthew and Mark to be written, circulated, and become well-known. This puts the writing of Matthew and Mark at 46 AD.
Christian theology regarding the resurrection was robust immediately after the death of Jesus and accounts describing the events were written down - at the very latest - within 16 years of the death of Christ. Paul’s letters, Acts, Luke, Mark, and Matthew were all written in the lifetimes of eye-witnesses and circulated in the area were the crucifixion and resurrection occurred. It is reasonable to conclude that the Christian doctrine of the resurrection was not a late invention and that the written accounts of Jesus were written by eye witnesses to the actual events.
 I think I first heard this argument on Stand to Reason, but I can’t find the exact reference.
 1 Corinthians 15:3-5
 Galatians 1:17-21
 Galatians 2:1
 J. Warner Wallace, Cold Case Christianity, David C. Cook Publishing, 2013
 Acts 1:1
 1 Timothy 5:17-18
 1 Corinthians 15:3-5
 1 Corinthians 11:23-25
 Luke 1:1-4