One of the things that has come down in Church tradition, with a small t, is that when St. John the Evangelist was very old, he gave a homily in Ephesus where his eloquence was overcome either by his feelings or his weak voice. All he said was “Little children, love one another.”
Of course, this is a quote from one of his epistles as well as a quote of Jesus. We had that reading this weekend, so I mention it. We have to love one another to be Christians, and too often we forget. It may not be encouraging to remember that the early Christians had the same problem, but we shouldn’t be too discouraged that people are human. We just have to keep plugging away, and let Christ’s life in us actually do stuff.
Anyway… a lot of people disbelieve in the Gospels as reliable information because they were supposedly written too long after the events in question. Most of this is caused by people refusing to believe that any Gospels could possibly have been written before the destruction of the Temple in the year 70. (Which is silly, because even if you are an atheist and don’t believe in prophecy coming true, you could certainly believe in apocalyptic prophecies of destruction being made left and right by Jewish prophets! Because that’s what they did!) But then, people refuse to believe that St. John the Apostle was St. John the Evangelist or St. John the author of Revelation, because God forbid he should have lived as long as everybody in the tradition says he did.
It’s been longer since 1968, now, than a lot of people think it’s plausible for people to have remembered what Jesus said. It’s definitely been longer since World War II. And yet, plenty of people are still alive who remember World War II and (despite drugs) the Summer of Love. A lot more people remember people who remembered.
Not everybody died young in the ancient world. The percentage of extremely elderly people today is somewhat higher; but extreme old age is mostly a matter of genetics, not of modern lifestyle. Modern lifestyle can get you surviving to the age of 70 or 80, but beyond that, you’re stuck with the stuff in your own DNA.