New Defender's Study Bible Notes
9 church. John apparently had written a previous letter to this church, but Diotrephes somehow intercepted it and refused to honor John’s request to help and hear the itinerant Bible teachers, even going so far as to excommunicate those who disagreed with him (III John 10).
9 Diotrephes. “Diotrephes” means “Nourished by Zeus,” and Diotrephes had chosen to keep his pagan name rather than to follow the custom of other Gentile converts and change it to a Christian name. He was evidently only half-converted from paganism, and resisted any teaching from John or other God-called teachers. Nevertheless, he had somehow gotten himself elevated by the congregation to the highest position of power in the church, able even to ignore or reject even the teachings of the Apostle John himself. He loved his position of power and was intent on keeping it. John was hoping he might soon be able to come and deal with the situation personally (III John 10), though his health and age might not allow (but note III John 13 and 14).