How It All Goes Down
Here we have three different letters, written at different times, to different people. Yet they're all loosely tied together by the same ideas. Oh, and the same author: a guy who only calls himself "the elder."
1 John
In the first letter, the elder encourages the Christians in his community to stay together. See, there are some naysayers who've been spreading lies about Jesus, and the elder really wants to set things straight.
First, Christians need to believe that Jesus was a for real a human being, not just some divine deity walking around on water everywhere. Second, Christians have to love each other. God is totally into love—it's his favorite things and he really wants all believers to just love their little hearts out.
Love. Love. Love. (Got it?)
This whole love thing doesn't apply to the naysayers, though (or any non-Christians, for that matter). No one is required to love those baddies or even pray for them. Probably because God isn't listening. The elder calls his opponents "antichrists" who are making God look bad.
Harsh.
2 John
In the second letter, the elder tells an "elect lady" to watch out for the naysayers in her midst. These guys might even try making their way to her church sometime soon, he says. (The horror!) He tells her not to even let them in the house because they're so wickedly evil and despicable. Antichrists, remember?
He also throws in some stuff about love…but seriously, be afraid. Be very afraid.
3 John
In the final letter, the elder writes to his pal Gaius to thank him for putting up some of the elder's friends as houseguests. Apparently, they're missionaries traveling in the area, and Gaius showed them the town. That's a lot better than this other dude, Diotrephes, who shut the door right in their faces—that guy is in big time trouble.
This third one is a pretty short letter, and the elder promises to visit soon so he and Gaius can catch up on their favorite subject: Jesus Christ.
And that's the last word we get from the elder.