Whoever makes a practice of sinning is of the devil, for the devil has been sinning from the beginning. The reason the Son of God appeared was to destroy the works of the devil.
8 He that committeth sin, This word, to commit, or to do, refers also to outward works, so that the meaning is, that there is no life of God and of Christ, where men act perversely and wickedly, but that such are, on the contrary, the slaves of the devil; and by this way of speaking he sets forth more fully how unlike they are to Christ.
The apostle, having alleged the believer's obligation to purity from his hope of heaven, and of communion with Christ in glory at the day of his appearance, now proceeds to fill his own mouth and the believer's mind with multiplied arguments against sin, and all communion with the impure unfruitful works of darkness. And so he reasons and argues, I.
Commenting on 1 John 3:4-10
He that committeth sin is of the devil,.... Not everyone that sins, or commits acts of sin, then every man is of the devil, because no man lives without the commission of sin; but he who makes sin his constant business, and the employment of his life, whose life is a continued series of sinning, he is of the devil; not as to origin and...