3 John in Wikipedia
The Third Epistle of John, usually referred to simply as Third
John and often written 3 John, is a book of the New Testament
attributed to John the Evangelist, traditionally thought to be
the author of the Gospel of John and the other two epistles of
John. This Epistle is the shortest book in the Bible.
Indications within the letter suggest a genuine private
letter, composed to Gaius to commend a party of Christians led
by Demetrius, who were strangers to the place where he lived,
and who had gone on a mission to preach the gospel (verse 7).
The purpose of the letter is to encourage and strengthen
Gaius, and to warn him against the party headed by Diotrephes,
who refuses to cooperate with the presbyteros who is