John 21:24
This is the disciple who testifies about these things, and wrote these things. We know that his witness is true.
World English Bible (Public Domain)
In context
Before · John 21:22–23
22Jesus said to him, “If I desire that he stay until I come, what is that to you? You follow me.” 23This saying therefore went out among the brothers that this disciple wouldn’t die. Yet Jesus didn’t say to him that he wouldn’t die, but, “If I desire that he stay until I come, what is that to you?”
24This is the disciple who testifies about these things, and wrote these things. We know that his witness is true.
After · John 21:25
25There are also many other things which Jesus did, which if they would all be written, I suppose that even the world itself wouldn’t have room for the books that would be written.