I testify unto every man that heareth the words of the prophecy of this book,If any man shall add unto them,God shall add unto him the plagues which are written in this book:and if any man shall take away from the words of the book of this prophecy,God shall take away his part from the tree of life,and out of the holy city,which are written in this book.Revelation 22:18-19 RV
I have often thought about what the faith would be like if all that survived was John's Gospel. What would be missing?
Many things. The Infancy narratives being the most obvious. Our understanding of the Last Supper would be very different, if we were to have it all. The Transfiguration, The Ascension, The Sermon on the Mount, The Prodigal Son. The list is obviously huge.
What would we be left with?
Just imagine if Paul's letters had not survived, and John's received a greater prominence? And (if one assumes that Revelation is genuinely Johannine) how would our view of God be altered if Revelation assumed a larger percentage of the New Testament?
I would love to study this idea in greater detail.