Some people have trouble accepting the accuracy of the Gospels. Even if we accept that some of the New Testament was written just 20 to 30 years after the Resurrection, that’s still 20 or 30 years. That’s a lot of time. Dr. William Carroll put the dating of Mark in the 40s. Even so, that’s a whole decade later.
Do you remember a conversation you had 10 or 20 or 30 years ago?
Would you remember it well enough to record it accurately today?
One reason we can believe the Gospels were recorded accurately is simply that Christ was (and is, of course) a teacher. I explore this briefly at New Evangelizers: Christ the Teacher and the Accuracy of the Gospels