I’ve included verses 15-17 for the sake of this discussion but will detail in a week or two.

12 I am writing to you, little children,
because your sins are forgiven for his name’s sake.
13 I am writing to you, fathers,
because you know him who is from the beginning.
I am writing to you, young men,
because you have overcome the evil one.
I write to you, children,
because you know the Father.
14 I write to you, fathers,
because you know him who is from the beginning.
I write to you, young men,
because you are strong,
and the word of God abides in you,
and you have overcome the evil one.
Do Not Love the World
15 Do not love the world or the things in the world. If anyone loves the world, the love of the Father is not in him. 16 For all that is in the world—the desires of the flesh and the desires of the eyes and pride of life—is not from the Father but is from the world. 17 And the world is passing away along with its desires, but whoever does the will of God abides forever.

This section has also left me scratching my head more than a few times. Many have an opinion on its thrust and value but not all agree. A friend and I have been memorizing 1st John so we’ve been kicking around this section a lot as to its practical theology. After examining in more detail this is my conclusion. MacArthur contends that basically it is a rhetorical call for there being room at the table for all stages of maturity in the Christian walk (my loose paraphrase for his comments). I would agree with that and would add the fact that John really doesn’t give a greeting to his letter. I would maintain (like Yarbrough from Baker Exegetical Commentary) that this is his delayed greeting. Remember how he began his letter by declaring rhetorically that “God is light and in Him is no darkness”. He then expressed the reality of the gospel in light of God’s holiness and our sinfulness. John then proceeded to give us tests for that forgiven position. Now it appears he has stopped mid thought to greet his readers. I do think he’s doing that but I think he’s doing much more. Yarbrough (who sought council from Kruse, Stott, Bruce, Smalley) maintains this greeting is reflexive (vs 12-13) and reflective (vs 14) concluding with a command in vs 15-17 (first of only ten in 1John) to not love the world. His appeal/command appeals to one group of people “his beloved children” (using padia and teknia-same crowd from a different angle because of the change in verb tense, present active indicative to aorist active indicative). These children are spoken to in two groups older and younger. I quote Yarbrough because he states better the transition that I have tried to summarize:”John’s message is that God is light (1:5). He has traced out many implications of this in previous verses. Most of all for present purposes, in 2:12-14 he has at some length detailed the spiritual status and profile of his readers in whose lives the divine light shines (2:8) and who are therefore not groping blindly in Stygian gloom (2:11). Thanks to their standing vis-à-vis the light of Father and Son, great benefits are thirs, among the greatest of which is that they are not helpless before the predations of the liar and murderer (John 8:44) who is the evil one (1 John 2:13-14). Rather, they have conquered him. One this basis John is in a position to move from an expository or indicative mode to the imperative.”1

1. Technically speaking, apapate is subjunctive, not imperative, but in Hellenistic Greek a phrohibitive Imperative combines a negative particle (typically may) with a subjunctive verb for an imperatival sense. The computer software Accordance rightly tags such “subjunctive” forms as imperatives when they occur with this meaning. See Wallace 1996: 487 who points out (note 99) that there are only eight true aorist imperatives In prohibitions In the NT; the rest are morphologically subjunctives.