Why did the writers of the New Testament wait so long before writing about the events of Jesus? Why didn't they write the events down as they were happening? Even if the Gospels, for example, were written before 50 A.D., doesn't that mean it was 20 years between the actual events and the recording? Doesn't that mean that the accuracy can't be trusted because they were recorded so long after the actual events?
We are not able to enter into the minds of the New Testament writers and tell you why they waited for years before writing things down. However, we can offer some possible explanations.
First of all, it is an assumption to say they didn't write things down until many years afterwards. It's certainly possible that things were recorded, used in writing the basis of the Gospels, and then the finished product was disseminated throughout the Christian church. This is not a very strong argument. It is merely offered as a possibility since there seems to be evidence of a common document that existed before Matthew, Mark, Luke, and John, and one or more of them draw from it when writing the Gospels. The document called "Q" is proposed for this. Q stands for quelle, or 'source.'
Second, people don't normally write things down as they happen. We experience something and then later realize it was significant. Then collaboration is often used with other witnesses when recounting what happened so that an accurate report can be recorded.
Third, not everyone knew how to read and write. We are so accustomed to the idea of being able to read and write that we take it for granted and assume that people of the New Testament time could do the same. But the fact is, the great majority could not read or write. Many people would use hired scribes who would write documents for people. The documents would then be considered the original person's writing. Therefore, a lot of writings would not occur until later.
Fourth, just because something is written 10, 20, or 30 years after an event does not mean it is not reliable. The Jewish people of that time were storytellers, but not in the sense of making something up. Truth was very important to them. After all, the Old Testament included the statements, "You shall not bear false witness against your neighbor" (Exo. 20:16), and "You shall not lie" (Lev. 19:11). So, when writing something down even decades later the truth was very important, and the Jews were practiced at conveying truth through stories and by memorization. Furthermore, the accounts could be verified by others who would have been eyewitnesses to the accounts.
Fifth, though not all of the eyewitnesses were still alive, a great many were. It would not take much for the writers to have access to the people in the area for verification of stories. After all, people worked where they lived, and most people would not venture more than 20 or 30 miles from their homes.
Sixth, God was able to inspire the writers of the New Testament to be able to recall the events properly. Furthermore, God could certainly put various individuals in the writers' paths who would have information that could then be verified and recorded.