3 John 1

"The elder, To my dear friend Gaius, whom I love in the truth." NIV translation 

John begins this letter with a greeting that could either describe his position as a leader of the church or an older man as both descriptions are accurate.

3 John 2

"Dear friend, I pray that you may enjoy good health and that all may go well with you, even as your soul is getting along well." NIV translation

He prays for all three parts (mind, body, and spirit) of his friend. Gaius evidently had health problems as well as a mental struggle to deal with a situation in the local church. His spirit was well as he was a believer in Jesus Christ and he was listening and following the Holy Spirit.

3 John 3 & 4

"It gave me great joy to have some brothers come and tell about your faithfulness to the truth and how you continue to walk in the truth. I have no greater joy than to hear that my children are walking in the truth." NIV translation

This passage brings us to the example of the man who is putting his body into action. Even though he had health problems, Gaius was showing hospitality to those that were going around and sharing the gospel. He knew what was right and put it into action which gave the apostle joy. This joy is much the same as a parent that sees their child growing up and living as they were taught. John thinks of him as his child because he evidently led Gaius to faith in Jesus Christ. This is the same relationship that Paul spoke of near the end of his first letter to the Corinthians.