Like the Old Testament, we do not have the original documents by the writers of the New Testament. But the good news is we have thousands of copies to compare, and we have many that are extremely close to the originals. This gives the New Testament documents a huge advantage over other ancient writings, which are often limited to just a few, and those few are often hundreds of years later than the originals. In addition, we have thousands of quotations from early church fathers, giving us an even better idea of what the original documents said.
Occasionally there was a problem in acceptance of the New Testament manuscripts. For instance, in the case of Hebrews, there was uncertainty of the book’s authorship, which presented a temporary obstacle to universal acceptance. A few other letters came from some distance away, so it took some time for all areas to accept them. Again, like the Old Testament documents, there are some today who are concerned about oral tradition since the biographies of Jesus were not written for some 30 years after his death and resurrection. But the response is the same – ancient peoples had amazing abilities to memorize a great amount of material. Plus, in the case of Jesus, he had disciples who followed him around. The job of the disciple for any rabbi was pretty simple; he had to simply listen to the rabbi and memorize what he had to say.