24 This disciple is the one who bears testimony and has written about these things, and we know that his testimony is true.
25 Now there are also many other things that Jesus did, which, if everyone was written down, I suppose that even the world itself would not have room to contain the books to be written.
John does not give his name, but we can be certain that it is John, who wrote this gospel, l the disciple of Jesus, and brother of James,. It is thought that it was around the year 100 AD when he wrote his account of the things that Jesus said and did. This would mean that John was quite an old man, probably well into his eighties, or even nineties.
He was recalling his memories of Jesus.
Some may wonder if John would have remembered with accuracy the things that had happened eighty years earlier. From personal experience I can recall things that were said to me, and events that occurred over sixty years ago. Others will be able to say something similar from their experience.
We must remember that people probably had a greater skill of remembering things than we do. Most may not have been able to read, therefore, it was important to have the memory finely tuned to remember details over great lengths of time.
Obviously John could read and write, but he would still have the same memory skills as others.
Also john had the advantage of being a witness to the greatest events in history.
However, John had another great advantage. He was a man who was full of the Holy Spirit, and it was the Holy Spirit who inspired John in the writing of the gospel.
It was the Holy Spirit who guided him into what he should include and what he should leave out.
From what John has written in verse 25 it is clear that he omitted most of the things that Jesus said and did. However, the Holy Spirit guided him to include all that is necessary for everyone to believe that Jesus is the Christ and to receive life in His name:
31 However, these things have been written so that you might believe that Jesus is the Christ, and that by believing you might have life in His name.