As I progressively read 1, 2 and 3 John I see that each letter becomes more and more personal. 1 John seems to be written to a general audience, 2 John written more specifically to an unnamed lady (possible this may have been a family in the church) and then 3 John is a letter written direct to a dear friend of His. Each one of these short books has the common thread in the message of truth and love.
In the same sense we see a progression in the messages from John warning us of false teachers and deceivers working diligently to take advantage of new believers and infiltrating the church. Here in 3 John we see the work of one that has made it into the church and turns it into something of his own, not trusting in God and discouraging new believers from being a part of the church.
John commends his friend Gaius for his faith and willingness to be a part of spreading the gospel through being hospitable and receiving strangers (fellow believers) into his him home. John shows us the hospitality that Gaius shows is because of the love he has for Christ, living in the truth and loving others through this gift is an example we need to imitate. “Dear friends, do not imitate what is evil but what is good. Anyone who does what is good is from God. Anyone who does what is evil has not seen God.” (vs.11) If we continue reading on we can see the comparison of evil with good in the opposite actions of Diotrephes in rejecting believers and who loves himself first and not God.
Again John repeats his wish of meeting a friend face-to-face as in his last letter, making the letter and relationship seem more personal. I see this as a challenge to make more efforts to be more intentional about meeting together face-to-face with our brothers and sisters in Christ.