....and keep yourselves from idols.
That is the last sentence in the first letter of John.
Someone told me once (perhaps my uncle, the amateur theologian) that in Jewish literature, often the most important thing was left for last. This last sentence carries a lot of freight.
Keep yourselves from idols. What does this mean? What is an idol? What are the idols we should keep ourselves from?
I think the right answer to this is, "What do you think?"
In the meantime, the other theme of this letter is: Love one another. Over and over again, we hear these simple words: Love one another. Love one another in truth and action. Don't just talk about it. Do it. Show it.
Not that there aren't some things to wrestle with (though the basic premise is easy for figure out). John seems to think that once we come to faith (and have God's DNA residing in us), we don't sin any more. I would like to talk with Martin Luther about this, because he is the one who said that we were always 100% saint and 100% sinner. And it is my experience as well that even though I have God's Holy Spirit residing in me, I do still sin, and need to be "born again from above" every day.
Then there is the part about antichrists. Please notice that there are "antichrists" and not one Antichrist, with a capital "A". This is not about a prediction about end times, but it is about every enemy and opposite of Christ, in every time.
So children of God,
Love one another. In word and deed. But mostly, in deed.
Believe that you are, indeed, what God has called you: children of God.
And, keep yourselves from idols.