What does 3 John 1:4 mean?

John not only approves of Gaius's leadership, he says, "I have no greater joy than this, to hear of my children walking in the truth." Gaius would have taken great comfort in John's words, especially in light of the difficult actions of Diotrephes (3 John 1:9–10). John speaks of joy in his other two letters (1 John 1:4; 2 John 1:12) and often specifically includes that word in his record of the teachings of Jesus (John 3:29; John 15:11; John 16:20–24; John 17:13). It is unclear whether John considers Gaius as one of the "children" mentioned, or if these children are the congregation Gaius leads. In either case, John rejoices—believers are living according to God's truth despite difficult times! Whatever problems may be caused by poor examples such as Diotrephes, men like Gaius and Demetrius are leading these believers well.