The same man did a very good, in my opinion, transaltion and examination of The Didache (The Teaching). It is at: http://bswett.com/1998-01Didache.html
His closing paragraph: Certainly Barnabas and Paul were “The Apostles to the Gentiles.” If the Didache is a sample of their teaching, as it certainly seems to be, then it must be dated no later than AD 49 because that was when they went their separate ways. The most probable date is either AD 44 or AD 47. In either case, those dates are earlier than anything in the New Testament. Therefore, I believe the Didache is the earliest Christian document we have. Although rightly regarded as a church handbook and not a Gospel or absolutely based on the teachings of Jesus, it provides valuable insights concerning the moral doctrines, theology, rituals, esoteric operations and congregational testing of apostles and prophets, and the basic organization of First Century Christianity.
There is no significant evidence that The Didache is even authentic. Nobody ever mentioned it until centuries later.