There is much about the Bible that is uncertain. It is a gift.
Today, the calendars of many western church bodies recognize John, Evangelist and Apostle. To be honest, it's an idea that is recognized, more than a certain person.
There is the tradition, of course, that John, the beloved apostle of Jesus, wrote the Gospel According to John, the three Epistles of John, and Revelation. Koine Greek scholars will tell you that the Greek in Revelation is not as well written as the Greek in the Gospel and epistles, so most are pretty sure "John of Patmos" is not the same John, whatever the tradition might say. The authorship of the other pieces with "John" attached is questioned, although there seems to be likelihood that these were all products of a "Johannine Community," That is to say, there was a community that identified with someone named John, perhaps founded by the apostle, perhaps not, but used poetic language and lots of symbolism (particularly light and darkness) in their understanding of God and Jesus.
(As a side note, let me say a bit about the "Gospel of Judas," which was published a few years ago, and how that gospel had Judas being cognizant of his cosmic role in betraying Jesus. There was much talk about how Judas was really a hero, doing God's work for the salvation of the world, etc. There was also general acknowledgment that it was a gospel written later than the canonical gospels. My thoughts at the time was that this very likely didn't tell us anything about the historical Judas and I wished the conversation would turn from that aspect of the gospel Much more interesting to me was that there was a community, however small, that told this story to each other and understood Judas---and the crucifixion of Jesus---in this way. But I digress.)
There are people for whom it is very important to believe that the authorship of the gospel, the epistles, and Revelation are all from one person, the beloved disciple, John. It was, perhaps, what was taught to them by a beloved pastor or Sunday school teacher, and to have the authorship questioned is to question these beloved people in their history, the people who played foundational roles in their faith.
I sympathize with this. No one wants to learn that everything you thought you knew was wrong (Note the influence of comic book hyperbole on my writing. But again, I digress.)
One of the things I struggle with is transmitting to people who are not theologically trained how to read the Bible with reverence and spiritual insight without needing the Bible to be all the things we may have been told it was in Sunday school.
For me, the benefit of this understanding is freedom. We are free to read the Bible, to wrestle with it, to argue with it, and still find within it the Good News of the Reign of God come near.
I realize that some of what I do in this blog is what was once called "de-mythologizing" the scriptures. It's not really my intention to do that completely, as I think we need to approach the bible with a more mythological mindset. It was written in a time and place that was saturated with myth and the symbolism and slant-told-truth (a poetry reference) that myth brings us.
But myth requires interpretation and we tend to want reportage that leaves no room for interpretation. Just the facts, please.
We cannot, however, read, "In the beginning was the Word, and the Word was with God and the Word was God" as strict reportage, a piece of cut and dried fact. It is full of theology and philosophy of the first century Greco-Roman world. Is there truth to be found within this language? Certainly. But it's not the truth of "a car crash occurred on Loop 610 at 5:43pm this afternoon."
(By the way, I made that up---I don't know if there was a car crash anywhere on Loop 610 today. It's an illustration to get to a broader truth.)
This is such a bigger issue than can be covered in a blog post, but if you're the sort for whom it is important to believe everything you're beloved teachers told you in your youth, I want to gently and with as much love as possible tell you that they were doing the best they could with the information they had. We all are, and we're all wrong sometimes.
And maybe the authorship of all these Johannine pieces of literature are not from one pen, from one person. We still receive them as scripture, handed down through the ages. If you were the sort to study the history of interpretation, you'd find that the understanding of these scriptures has changed through the centuries---sometimes for the better, sometimes for horrific worse. (The Gospel of John has been cited as a source for justifying antisemitism, for example.)
That there is uncertainty in this history, for me, gives me the freedom to wrestle with what these scriptures mean for me---for us---today. We can study the way words were used in the time they were written and gain insight to what they meant to the first people to hear them, but only to a certain extent. We ultimately need to find the key to the scriptures for ourselves, for our time, for the love of the world as it is today.
No matter who wrote it, we can all benefit to ponder these words:
Beloved, let us love one another, because love is from God; everyone who loves is born of God and knows God. Whoever does not love does not know God, for God is love.
[I John 4:7-8]