3 John 4 I have no greater joy than to hear that my children walk in truth.
John’s children are those he is discipling in the faith. This is one of those verses that can’t be just taken as is; it needs to be considered in context. That’s easy because 3 John is a very short letter with only one chapter. Verse 4 was written along with John’s thoughts concerning a certain man, Gaius. John explains that Gaius welcomes and shows hospitality toward other Christians (missionaries, etc) who are traveling. The specific statement is that Gaius does faithfully (reliably) whatever he does for the brethren, and for strangers (v5).
John then contrasts another man of the church, Diotrephes, with Gaius. Diotrephes thinks highly of himself, speaks against leadership, and does not show hospitality. John then goes on to say, “Do not imitate what is evil, but what is good.” (v11)
John also brings up Demetrius, who has a good “testimony” from others and from the truth. In other words, his words and actions matched his faith.
So then, when John says in verse 4, “I have no greater joy than to hear that my children walk in truth,” I am reminded that not only can we be joyful in our faith, but we can also bring joy to others by living out our faith well, walking in truth, and having a good testimony.