Gaius seems to have housed and taken care of traveling missionaries, perhaps some sent out by John. John writes to him,
You will do well to send them on their journey in a manner worthy of God. – 3 John 1:6
“You will do well” is an ancient expression that basically means “please”. John is politely requesting that Gaius would send the missionaries on their way in a manner worthy of God, with great generosity. John is likely asking Gaius to stock them with food, money, and whatever else they might need. Why?
For they have gone out for the sake of the name, accepting nothing from the Gentiles. – 3 John 1:7
They had gone out for the sake of the name of Christ, to preach the gospel of Christ. And in this they accepted nothing from the Gentiles. From context, we can see that he’s using the word “Gentiles” to mean “unbeliever”, as Gaius and Demetrius were themselves ethnic Gentiles. This probably shows that the early church had thought of themselves as a new Israel.
Why did they accept nothing from unbelievers? Perhaps it was to make clear that they weren’t preaching the gospel for the sake of monetary gain, as some public speakers sought to do. They weren’t there for the Gentiles’ money; they were there for there souls.
So, what is John’s conclusion to that?
Therefore we ought to support people like these, that we may be fellow workers for the truth. – 3 John 1:8
Notice how John includes himself here. It wasn’t just Gaius’s responsibility. It was the Apostle John’s too. And if their responsibility, why not ours too? Why should we not be fellow workers for the truth?
Christ the King has given the church an objective: to go and make disciples of all nations. Now, it’s true that not all are called to be missionaries, but all are called to somehow take part in this mission. Whether it’s showing hospitality to missionaries or giving financial support or training up missionaries to go or evangelizing in our own contexts, there is much work to be done, and we are fellow workers for the truth.
Sheep, we have to be careful to not shirk our responsibilities for the truth. We have been saved by grace in order to make His glory known.