The writer of this Gospel did not identify himself as such in the text. This is true of all the Gospel evangelists. Nevertheless there is evidence within this Gospel as well as in the writings of the church fathers that the writer was the Apostle John.
The internal evidence from the Gospel itself is as follows. In 21:24 the writer of "these things"(i.e., the whole Gospel) was the same person as the disciple whom Jesus loved (21:7). That disciple was one of the seven disciples mentioned in 21:2. He was also the disciple who sat beside Jesus in the upper room when He instituted the Lord's Supper and to whom Peter motioned (13:23-24). This means that he was one of the Twelve since only they were present in the upper room (Mark 14:17; Luke 22:14). The disciple whom Jesus loved was also one of the inner circle of three disciples, namely Peter, James, and John (Mark 5:37-38; 9:2-3; 14:33; John 20:2-10). James died in the early history of the church, probably in the early 40s (Acts 12:2). There is good evidence that whoever wrote this Gospel did so after then. The writer was also not Peter (21:20-24). This evidence points to John as the disciple whom Jesus loved who was also the writer of this Gospel. The writer claimed to have seen Jesus' glory (1:14; cf. 1:1-4), which John did at the Transfiguration. There are several Johns in the New Testament. This one was one of Zebedee's sons who was a fisherman before Jesus called him to leave his nets and follow Him.
"To a certain extent each of the Gospels reflects the personality of its author, but in none of them is there a more distinctive individuality manifested than in John."1
The external evidence also points to the Johannine authorship of the fourth Gospel. Irenaeus, the bishop of Lyons (c. 130-200 A.D.), wrote that he had heard Polycarp (c. 69-155 A.D.), a disciple of John. It was apparently from Polycarp that Irenaeus learned that, "John, the disciple of the Lord, who also had leaned upon His breast, had himself published a Gospel during his residence in Ephesus in Asia."2Other later church fathers supported this tradition including Theophilus of Antioch (c. 180 A.D.), Clement of Alexandria, Tertullian of Carthage, and Tatian.3Eusebius (fourth century) also specifically mentioned that Matthew and John among the apostles wrote the Gospels that bear their names.4
Some scholars have rejected this seemingly clear evidence and have refused to accept Johannine authorship. This criticism comes from those who hold a lower view of Scripture generally. Answering their objections lies outside the purpose of these notes.5
