1. Title. In the ancient Greek manuscripts the title is simply Iōannou G, literally, “Of John 3.” See on the Title of the First Epistle (p. 623).
2. Authorship. Had there been no second epistle, the authorship of the third might have been a matter for considerable dispute. But the similarity in style between the second and third epistles points to a common authorship, so that once John is accepted as the author of the second epistle, he may also be accepted as author of the third.
3. Historical Setting. The epistle is clearly a personal letter written to an unidentified Gaius, a faithful Christian who is highly commended for his hospitable charity toward traveling teachers. Two other characters are named: Diotrephes, a contentious leader; and Demetrius, who is possibly one of the traveling teachers. The picture that emerges from what is written about these three men represents an advanced stage of development in the Christian church, and suggests that this epistle was written after the second, and consequently still closer to the end of John’s life. The ministry of itinerant preachers, or of visiting brethren, appears to be well established (vs. 5-8); Diotrephes assumes the power to cast from the church, possibly by a form of excommunication (v. 10), those of whom he does not personally approve; and the apostle’s authority has been undermined by the Diotrephes faction (vs. 9-11). All this points to a development of the situation revealed in the second epistle, and makes the third the last in the trio of letter preserved to us. This is not to say that John wrote no other letters. There is no evidence to prove that the letter referred to in v. 9 was the second epistle, although it is an attractive possibility; and there is no way of determining the length of time that passed between the writing of the second epistle and that of the third, but it seems probable that the interval was brief, since the letters are so closely related in style and content.
4. Theme. This is simple and direct. Whereas the second epistle was written to warn against itinerant false teachers, this one is sent to oppose the schismatic tendencies exemplified by the actions of Diotrephes. It is probable that Diotrephes was the elder of the church and that he had accepted some of the false teachings of the Gnostics (see pp. 625, 626). When John wrote to the churches to rebuke such false teaching, Diotrephes appears to have refused to read the letter to the members (v. 9). Visiting ministers who may have been sent by John were also refused a hearing, and those who listened to them privately were signally disfellowshiped by this arrogant man.
By writing to Gaius, John endeavors to ensure the delivery of his message to the loyal members. He may have been preparing them to accept a change of church elders when he should come and “remember” the deeds of Diotrephes (v. 10).
The same spirit of tender personal affection is evinced in this letter as in the apostle’s other writings, and, over and above the immediate purpose of the epistle, there shines the beauty of the apostle’s own character and the inspiration that he brings to his readers in all ages.