3 John 1:4 Updated American Standard Version (UASV)
3 For I rejoiced greatly when the brothers came and testified to your truth, just as you are walking in the truth. 4 No greater joy do I have than this, to hear of my children walking in the truth.
That is, true Christians; living in accordance with the truth, for this constitutes the essence of true Christianity.
“When people we mentor and disciple are walking in the truth as God has commanded, we are filled with joy and pleasure.” – David Walls and Max Anders