Andreas Köstenberger demonstrates, “At the very outset, John’s gospel claims to represent apostolic eyewitness testimony regarding Jesus’s earthly ministry.” This is a crucial component of the internal evidence presented to support Johannine authorship and determines whether the gospel is truly an eyewitness account or merely a later apostolic writing. D. A. Carson also concludes, “The Fourth Gospel can be accepted as what it manifestly purports to be: a reliable witness to the origins, ministry, death, resurrection, and exaltation of Jesus the Messiah.” Following the opening testimony, additional internal evidence refers to the author being the “disciple whom Jesus loved.” This title first occurs at the Last Supper, then in the high priest’s courtyard following the arrest of Jesus, next at the foot of the cross where Jesus was crucified, and lastly at the empty tomb, following the resurrection of Jesus. From these references, this writer and Köstenberger conclude, “the internal evidence points unequivocally to John, the son of Zebedee as the author of John’s gospel.”
External evidence supporting Johannine authorship exists first with the early church fathers, all of which unanimously supported John, the son of Zebedee as the author. In addition, as Köstenberger illustrates, “Irenaeus used John’s gospel to refute Gnostic teaching in the second half of the second century AD, [which] cemented the gospels place in the church’s canon once and for all.” From the second up until the middle of the eighteenth century, the church and most scholars are united in attributing the Fourth Gospel’s authorship to John, the son of Zebedee. During the mid-eighteenth century, literary criticism attempted to discredit Johannine authorship, but today most scholars again agree John, the son of Zebedee is the most likely author. It is imperative to show John authored the fourth gospel because as Köstenberger highlights, “It safeguards this gospel’s character as an apostolic eyewitness testimony.”
The most popular view on the place of writing comes in the form of external evidence from Irenaeus, who said, “John… published the Gospel while he was a resident at Ephesus in Asia.” This, however, does not mean a community of believers in Ephesus was his primary audience. The date of writing is linked closely with two events: the destruction of the temple in AD 70 and Peter’s martyrdom around AD 65. Based on these events, this writer and Köstenberger believe, “John probably wrote his gospel in the AD 80s in Ephesus, primarily to Diaspora Jews and to Gentiles attracted to the Jewish faith, but ultimately to the church at large.” Additional external evidence favors this date, as coins from that time period have been discovered bearing Domitian as Dominus et Deus (Lord and God) the exact Latin translation of Thomas’s confession.
The destruction of the temple in AD 70 was reminiscent of the Babylonian exile, since there was now no temple to offer sacrifices in. Without a sacrificial system in place and no priesthood, John used these dilemmas as a window of opportunity to evangelize Jews; by showing how Jesus, the Messiah became the final atonement for sin. John then shows how Christ, the Son of the living God had become Prophet, Priest, and King. John wanted his readers to recognize the universal nature of Christianity, found in salvation by faith. Köstenberger further demonstrates, “The gospel’s audience is not limited to its first readers and intended recipients; it also extends to us. And in God’s providence, we may benefit from John’s gospel by deriving spiritual insights from it not even envisioned by John himself.” John’s gospel plays a major role in the spiritual journey of believers and non-believers today in its ability for edification of believers and evangelism for non-believers. The “good news” of John, while not considered a synoptic, is just as relevant today as it was for its intended audience, making it for many the “preferred gospel.”
Carson, D. A. The Gospel According to John: The Pillar New Testament Commentary. Grand Rapids, MI: William B. Eerdmans Publishing, 1991.
Köstenberger, Andreas. Encountering John: The Gospel in Historical, Literary, and Theological Perspective, 2nd Edition. Grand Rapids, MI: Baker Academic Publishing, 2013.
 Andreas Köstenberger, Encountering John: The Gospel in Historical, Literary, and Theological Perspective, 2nd Edition, (Grand Rapids, MI: Baker Academic Publishing, 2013), 4.
 D. A. Carson, The Gospel According to John: The Pillar New Testament Commentary, (Grand Rapids, MI: William B. Eerdmans Publishing, 1991), 40.
 John 13:23
 John 18:15
 John 19:26-27
 John 20:1-8
 Köstenberger, Encountering John, 5.
 Köstenberger, Encountering John, 6.
 Köstenberger, Encountering John, 6.
 Ibid., 6.
 Ibid., 8.
 Köstenberger, Encountering John, 10.