This is addressed to the beloved Gaius, but there are several of this name mentioned in the New Testament. The second epistle describes those who are to be refused; this shows who are to be received.
After declaring that the greatest joy of the apostle was to hear that his children walked in the truth, the apostle commends Gaius for receiving and helping on those that traveled about doing the Lord's work. He denounces Diotrephes who did not receive such, and who even put some out of the assembly; the evil of clericalism being clearly manifest in this. Gains was not to follow evil. The apostle commends Demetrius, and sends greetings to Gaius and to the friends.