2 Beloved, I pray that all may go well with you and that you may be in good health, as it goes well with your soul. 3 For I rejoiced greatly when the brothers came and testified to your truth, as indeed you are walking in the truth. 4 I have no greater joy than to hear that my children are walking in the truth.
It reads like a personal letter where John inquires into his health and general well-being. How happy he is to hear good reports about him from others. John writes as though he is delighted to hear how he is doing.
So what is he delighted in?
1. Others came and told him how well Gaius was doing. How he was walking in the truth.
2. Like a believing parent he is simply delighted that one of his children is also a believer. It simply fills him with joy.
Is Gaius a literal child of the John? No. He is most likely a person that John brought to faith in the Lord, and thus considers him to be a child IN the Lord.
I know from talking with my own parents how much joy they have that all six of their children know and love the Lord. Too many believing parents don't know that joy. It's hard for them to know their children are rejecting God.
I also know that it's my fondest desire for my son to grow up and love the Lord. To figure out that God is real and does indeed make a difference in life.