This letter is a note of thanks and encouragement to an individual named Gaius. John had sent a letter to the church of which Gaius was a member, introducing and commending certain individuals, but a leader named Diotrephes refused to accommodate them. He opposed John’s authority to the point of actually expelling anyone who supported the people he had sent. Gaius, however, put these preachers up in his own home, enabling them to carry out their mission. John’s gratitude makes it clear that the church should provide a base of operations for traveling preachers who were walking in the truth. John also promises to come soon to set matters right.