John writes his third epistle to a faithful kingdom saint named Gaius. In this letter, he mentioned two other men (Diotrephes and Demetrius), one evil and the other good (1 Jn 3:10). Evidently, they were both leaders in the same church. John had written a letter to their church and sent it with certain brethren. They were rejected by Diotrephes, but received by Gaius and Demetrius.
Outline:
I. Introduction (v. 1)
II. Gaius (v. 2-8)
III. Diotrephes (v. 9-11)
IV. Demetrius (v. 12)
V. Conclusion and Greetings (v. 13-14)