John 21:24 (ESV)
This is the disciple who is bearing witness about these things, and who has written these things, and we know that his testimony is true.
It is only at the end of this long gospel account that John reveals his name, as the author of the book. He has not announced himself for the first 21 chapters. There would be nothing wrong with that, as we can see from Paul’s many letters, or Luke’s account of both his gospel and the book of Acts.
John, at the end, does want us to know he wrote it and that he can be trusted with the facts of the book. The world disregards the Bible accounts, as though there are make-believe stories, conjured up in the minds of religious fanatics. However, John boast that his testimony is true. The Greek word of testimony is martyria. This is where we get our English word martyr. As prophesied by Jesus, John was one of the few apostles who were not put to death for their testimony of Jesus. But that does not mean he was not a martyr. Note what he said at the beginning of his book, Revelation:
Revelation 1:9 (ESV)
I, John, your brother and partner in the tribulation and the kingdom and the patient endurance that are in Jesus, was on the island called Patmos on account of the word of God and the testimony of Jesus.
He was banished to a small island and held captive until his death, by natural causes. But he was there because he spoke of Jesus. As we bear witness of Jesus, we should expect some mis-treatment by the world.
Peter said it this way:
1 Peter 4:12 (ESV)
Suffering as a Christian
Beloved, do not be surprised at the fiery trial when it comes upon you to test you, as though something strange were happening to you.
Paul said it this way:
2 Timothy 3:12 (ESV)
Indeed, all who desire to live a godly life in Christ Jesus will be persecuted,
Don’t be surprised if you suffer for beating witness of the Light. The Dark (world) hates the Light (Christ).