1 John 2:1

These verses relate to the concluding subject of the foregoing chapter, in which the apostle proceeds upon the supposition of the real Christian's sin. And here he gives them both dissuasion and support. 1. Dissuasion. He would leave no room for sin: "My little children, these things write I unto you, that you sin not, Jo1 2:1. The design or purport of this letter, the design of what I have just said concerning communion with God and the overthrow of it by an irreligious course, is to dissuade and drive you from sin." See the familiar affectionate compellation with which he introduces his admonition: My little children, children as having perhaps been begotten by his gospel, little children as being much beneath him in age and experience, my little children, as being dear to him in the bonds of the gospel. Certainly the gospel most prevailed where and when such ministerial love most abounded. Or perhaps the judicious reader will find reason to think that the apostle's meaning in this dissuasion or caution is this, or amounts to this reading: These things write I unto you, not that you sin. And so the words will look back to what he had said before concerning the assured pardon of sin: God is faithful and just to forgive us our sins, etc., Jo1 1:9. And so the words are a preclusion of all abuse of such favour and indulgence.

— Matthew Henry's Concise Commentary (public domain)