John is kind of erratic in this section, bouncing from idea to idea and back again. There may be some sinews that connect all of it but, at least at the moment, I’ve having trouble finding them.
We are reminded that God loves us so much that he is willing to call us children. That’s not a God who is simply pacified or tolerant that you made it into heaven, it’s a God who did whatever it took to adopt you into His family. And as children of God, we shouldn’t be surprised that the world doesn’t understand us because they didn’t get Jesus either. And beyond that, there’s even more to come, we’ve not yet fully realized what it’s like to live as God’s children, that will come to fruition when Jesus returns.
Then a digression: whoever sins acts as if there are no laws, no right way to live. But Jesus comes and sets that right and also provides an example so that we indeed may know how to live (in effect, Jesus is the law). But you can’t keep on acting as if that example didn’t exist. We must follow Jesus and do as he did. To not do so is to ignore what he has done as if it is not real or binding. That is lawlessness, and a rejection of Jesus, and comes from his opponent.
Let’s just note here that John is kind of difficult to parse at times in this section. He moves between what seems very broad (“…everyone who hopes in [Jesus] purifies himself…) and very specific and direct (…whoever makes a practice of sinning is of the devil…). In general, it seems safe to assume that his reaction to sinful behavior is habitual, consistent sinning since earlier in the letter we are told that anyone who thinks he doesn’t sin is a liar. Nonetheless, John continues to affirm that there is righteousness in what we do and that are deeds can indeed be righteous. (It is at least passingly curious that the two verses in 1 John so far that deal with works themselves being considered righteous pass without any verse commentary in the ESV Study Bible notes, which bend Reformed. I do wonder how Calvinism would comment on this association.)
John continues to tie this together with our understanding of the greatest commandments, loving and being obedient to God and loving others. If you aren’t practicing righteousness or you don’t love your brother, you’re not a child of God. He uses Cain as an example of someone who was murdered his brother because his own deeds were evil and his brother’s were righteous. [Squirrel!] Then he jumps to the reminder that we shouldn’t be surprised that the world hates us (just talked about that a few verses ago). I suppose the connection probably is Cain’s jealousy and worldly reaction vs. what Abel was doing.
Regardless, we know that we have passed from death to life when we love others like God has loved us. This is tough one: “But if anyone has the world’s goods and sees his brother in need, yet closes his heart against him, how does God’s love abide in him? Little children, let us not love in word or talk but in deed and truth.”
Finally, we come back to loving God and keeping his commandments. Which is kind of baked into the previous thing because we are told that God commands us to believe in his Son and to love one another. And we know God abides in us because He has provided the Spirit.