The author of this gospel is John, one of Jesus’ disciples. John in his humility does not refer to himself in the first person. He calls himself “the one whom Jesus loved” (John 13:23, 19:26, 20:2, 21:7, 20) or simply “another disciple” or “the other disciple” (John 18:15, 20:2-4, 8). When he mentions a person named John, he is usually referring to John the Baptist. On one occasion Peter’s father is identified as John (John 21:15-17).
John also wrote The Epistles of 1, 2, and 3 John and The Revelation of Jesus Christ.
Like so many other New Testament books and epistles, it is impossible to set a firm date for this Gospel. According to the writing of the church fathers, the earliest possible date is about 69-70 AD, but it is more likely to have been written later, possibly around 85 AD. This date is well after the destruction of Jerusalem and the dispersion of the Jews (70 AD). Once the Jews were dispersed, they began using the Roman method of keeping time as a practical matter.
One evidence for this later date is that John, on at least one occasion, used the Roman method of counting time from midnight. (Compare John 19:14-16 with Mark 15:25.). The other gospels, written earlier, always use the Jewish method and calculate the morning hours to begin at dawn (about 6:00 o’clock Roman time). John mentions the specific hour of the day in John 1:39, 4:6, 4:52 and 19:14. The Gospel of John was the last of the four gospels written.
THEME AND PURPOSE:
John clearly identified his theme and purpose for writing: John 20:31 – But these have been written that you may believe that Jesus is the Christ, the Son of God; and that believing you may have life in His name.