1 and 2 John warn of multiple antichrists (1 John 4:3, 2 John 7).2 John 9, Anyone who goes too far and does not abide in the teaching of Christ, does not have God; the one who abides in the teaching, he has both the Father and the Son, is similar to multiple passages in 1 John.
Despite the brevity of 2 and 3 John, many common ideas and phrases are obvious.Ignatius (35-107), Papius, Iraneus and Origin (185-254) assigned John the son of Zebedee as the author of the Gospel of John.However, Papius identifies a separate John as the writer of the letters of John and Revelation, so there is some variance in early tradition as to authorship of the Johannine letters.2 John says Though I have many things to write to you, I do not want to do so with paper and ink; but I hope to come to you and speak face to face, while 3 John 13-14 has the remarkably similar I had many things to write to you, but I am not willing to write them to you with pen and ink; but I hope to see you shortly, and we will speak face to face.In both books the author rejoices over children walking in truth.Jesus says to the sick man, Do you wish to get well?
The sick man replies Sir, I have no man to put me into the pool when the water is stirred up, but while I am coming, another steps down before me" (John 5:6-7).
The Greek of Revelation is different and non-standard, probably because John wrote it as a letter without help.
The Gospel of John, though clearly coming from John, looks like it was a collaberative effort.
The identification of John the son of Zebedee as the author of this material is dependent on a combination of the writings of early church fathers and indirect evidence within these books.
Holding John the son of Zebedee to be the author of Revelation are the second century church fathers Justin Martyr and Irenaeus, along with third century fathers Clement of Alexandria, Tertullian of Carthage, Origen of Alexandria, and Hippolytus of Rome.
Identifying the apostle as the author of all the Johannine writings pulls their date of writing into the first century A. However, the perspective that the Gospel of John and Revelation have on the city of Jerusalem pulls their dates earlier still, as discussed in the page on the destruction of Jerusalem.