4 I can't tell you how happy I am to learn that many members of your congregation are diligent in living out the Truth, exactly as commanded by the Father.
5 But permit me a reminder, friends, and this is not a new commandment but simply a repetition of our original and basic charter: that we love each other. 6 Love means following his commandments, and his unifying commandment is that you conduct your lives in love. This is the first thing you heard, and nothing has changed.
Matthew Henry's Commentary on 2 John 1:4-6
Commentary on 2 John 1:4-6
(Read 2 John 1:4-6)
It is good to be trained to early religion; and children may be beloved for their parents' sake. It gave great joy to the apostle to see children treading in their parents' steps, and likely in their turn to support the gospel. May God bless such families more and more, and raise up many to copy their example. How pleasing the contrast to numbers who spread irreligion, infidelity, and vice, among their children! Our walk is true, our converse right, when according to the word of God. This commandment of mutual Christian love, may be said to be a new one, in respect of its being declared by the Lord Christ; yet, as to the matter, it is old. And this is love to our own souls, that we obey the Divine commands. The foresight of the decay of this love, as well as of other apostacies, or fallings away, might engage the apostle to urge this duty, and this command, frequently and earnestly.