John was present with Jesus throughout His ministry and faithfully understood and exhibited the behaviors of a true disciple. John 21:24 identifies this as John's testimony, and the very acknowledgment that it is him is enough for anyone familiar with him to know that it is true. John had passed the test of time. He was loyal, faithful, and full of integrity. His word was his bond; he did not need to say more than that because he was a true disciple in both word and action.

John tells us in John 20:31 why he wrote the book. He says, "But these have been written so that you may believe that Jesus is the Christ, the Son of God; and that believing you may have life in His name." John wanted us to understand that Jesus was indeed a man, a human being who grew hungry, thirsty, and tired, but He was more than a man: His spirit was divine. He had existed before being conceived in Mary's womb. He came to earth from heaven. And though it is a mystery beyond our understanding, John says Jesus was present at the beginning of creation. He was the One who spoke it into existence. John also made sure to be the kind of man people would believe when he spoke. His words were trusted because faithfully following Jesus produces a trustworthy testimony.