That’s a good question.  We know the Lord used John, son of Zebedee, to write five books of the Bible.  He wrote the Gospel of John, the 1^st, 2^nd, and 3^rd epistles of John, and Revelation.  Revelation is the last book in the Bible and is the last book that was written in the Bible.  Let’s see what we can find out about when John wrote his books and how old he was when he wrote the book of Revelation. 

It is thought that John wrote the Gospel of John around 85 AD, the epistles between 86-88 AD, and the book of Revelation around 90 AD.  While absolute certainty about the exact order of John’s writings may not be completely agreed upon, the accepted sequence…the Gospel, the epistles, then Revelation, is the general consensus of early Christian tradition and much of modern scholarship.

We read in Revelation 1:9, “I John, who also am your brother, and companion in tribulation, and in the kingdom and patience of Jesus Christ, was in the isle that is called Patmos, for the word of God, and for the testimony of Jesus Christ.”  Patmos was a small, rocky island situated in the Aegean Sea. Patmos is described as barren and relatively isolated, making it an ideal location for Roman authorities to send exiles or political prisoners.  Historians attest that such islands were often used as places of banishment. Patmos’s isolation and challenging terrain provided a setting that limited easy escape, allowing Roman overseers to maintain control over prisoners.   

Because of “the word of God, and for the testimony of Jesus Christ”, John was exiled to this island.  It is so unique that John was sent to Patmos to ‘shut him up’ because of his testimony for Christ, yet it was here that the Lord led John to write such an important book…the book that was used to complete the Word of God.  Indeed, the Word of God would not be complete without the book of Revelation.

There is no direct evidence to show John’s age, so we should not be dogmatic about this, but it is thought that John was in his early 90’s when he wrote the book of Revelation.  We know that James and John were brothers (Matthew 4:21).  Whenever we read of James and John together, James is always mentioned first, which indicates that he was older than John.  It has been estimated that John was in his late teens/early twenties when the Lord Jesus was crucified.  Writing the book of Revelation in his 90’s, we realize this faithful man lived a long life in service to the Lord. 

We know that John, along with his brother James, and their father were fishermen (Matthew 4:21).  The Lord Jesus gave James and John the name “Sons of thunder” (Mark 3:17), probably because of their boldness and courageous behavior.  James, Peter, and John were in the Lord’s inner circle (Matthew 17:1-2, Mark 5:37, Mark 14:32-33, etc.).  John’s humility is evident in his Gospel, where he never mentions his own name, but describes himself as, “the disciple whom Jesus loved.” (John 21:7, John 21:20).  At one time, Peter and John were called upon to defend the miraculous works they had done in the name of Christ.  After making their defense before the Sadducees, elders, scribes, and the High Priest, it was noted of them, “Now when they saw the boldness of Peter and John, and perceived that they were unlearned and ignorant men, they marvelled; and they took knowledge of them, that THEY HAD BEEN WITH JESUS.” (Acts 4:13).  Indeed, Peter and John were not educated, they were not trained in the ways of the Pharisees or Sadducees, their boldness made it obvious they had spent time with the Lord.  What a testimony…that their lives manifested their time with the Lord.  May the same be said of each one of us that know the Lord Jesus Christ as our savior.  (CC)  (724.6)