Just finished chapter 3, which first tells us we will see God just as he is when he appears for we shall be like him.
This chapter also tells us that sin is lawlessness and then goes onto explain what our relationship to sin should be.
One difference in my translation is in verse 9. Other translations say we are not able to sin if we are of God, which I believe contradicts other parts of the Bible. Rather I have translated it as ‘we are able not to sin’.
Clearly those that habitually sin are not from God, but saying that those of God never sin I think goes against 1 John 1:8.
The rest of the chapter goes onto talk about brotherhood and how we are to act as brothers.