It seems to me the purpose of the 3rd epistle of John was primarily to combat the error of Diotrephes, the error of the idea of one leader being supreme over the other leaders. He “wants to be the leader over them,” and disallows the visiting brothers to have any authority in his church. This is contrary to the teachings of the apostles. First of all, the apostles were co-equal to each other. Secondly, they were careful to appoint multiple, co-equal elders in each church. The wisdom of disallowing one human being to have all the power, is confirmed by the wise men and wise cultures and wise political systems of many or all eras.