THIS MIGHT SURPRISE YOU
The answer
John 20. The line is John 20:30-31, and most scholars take it as the Gospel's original ending. Then chapter 21 adds an epilogue and a second ending, in which a "we" vouches for the disciple's testimony (John 21:24-25).
Why it’s interesting
Every surviving manuscript includes chapter 21, and it is written in the same style as the rest. That is why some scholars think it was there from the start.
Scholarly consensus
Learn the Bible.
Not just the stories, but the history, authorship, and scholarship behind it.