Third Epistle of John
The letter commends Gaius for keeping strong in his faith in Jesus.  It tells Gaius to help people who are working along with him to spread the gospel message.  It says that Diotrephes doesn't like John's message and John hopes to come to visit and to tell others that Diotrephes is wrong when he doesn't accept the Christian message and people who are telling that message.  John also says that Demetrius is living properly.  We don't know much about either of these men.