First John 2:29 is a transitional verse in the letter. Notice the use of the word “begotton” or “born.” Prior to verse 29, that word does not occur in all in the first two chapters, but it occurs ten times from this point forward. John’s focus from this point forward will be what it means to be in the family of God.
In verses 1–2, John has told us what we are: children of God. He has told us what we will be: like Jesus when we see his face someday. Now John tells us in verse 3 what we should be:
“Everyone who has this hope fixed on Him purifies himself just as He [Jesus] is pure.”
John further develops his point from verse 3 in verses 4–10.
Based on the sub-paragraph structure of the text, one could outline the passage as follows:
A. You are children of God, now and forever! – (vv. 1–3).
B. True children of God do not exhibit a sinful lifestyle – (vv. 4–6).
I. Don’t be seduced to sin. Those who exhibit a sinful lifestyle are unsaved – (vv. 7–10).