I John 3:4

Sin is incompatible with birth from God (Jo1 3:1-3). John often sets forth the same truth negatively, which he had before set forth positively. He had shown, birth from God involves self-purification; he now shows where sin, that is, the want of self-purification, is, there is no birth from God. Whosoever--Greek, "Every one who." committeth sin--in contrast to Jo1 3:3, "Every man that hath this hope in Him purifieth himself"; and Jo1 3:7, "He that doeth righteousness." transgresseth . . . the law--Greek, "committeth transgression of law." God's law of purity; and so shows he has no such hope of being hereafter pure as God is pure, and, therefore, that he is not born of God. for--Greek, "and." sin is . . . transgression of . . . law--definition of sin in general. The Greek having the article to both, implies that they are convertible terms. The Greek "sin" (hamartia) is literally, "a missing of the mark." God's will being that mark to be ever aimed at. "By the law is the knowledge of sin." The crookedness of a line is shown by being brought into juxtaposition with a straight ruler.

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. From the nature of sin and the intrinsic evil of it. It is a contrariety to the divine law: Whosoever committeth sin transgresseth also (or even) the law (or, whosoever committeth sin even committeth enormity, or aberration from law, or from the law); for sin is the transgression of the law, or is lawlessness, Jo1 3:4. Sin is the destitution or privation of correspondence and agreement with the divine law, that law which is the transcript of the divine nature and purity, which contains his will for the government of the world, which is suitable to the rational nature, and enacted for the good of the world, which shows man the way of felicity and peace, and conducts him to the author of his nature and of the law. The current commission of sin now is the rejection of the divine law, and this is the rejection of the divine authority, and consequently of God himself. II. From the design and errand of the Lord Jesus in and to this world, which was to remove sin: And you know that he was manifested to take away our sins, and in him is no sin, Jo1 3:5. The Son of God appeared, and was known, in our nature; and he came to vindicate and exalt the divine law, and that by obedience to the precept, and by subjection and suffering under the penal sanction, under the curse of it. He came therefore to take away our sins, to take away the guilt of them by the sacrifice of himself, to take away the commission of them by implanting a new natu…

3:4-10 This section discusses what it means to live a pure life (3:3). Being born into God’s family demands purification; a life of sin—a continual lack of purity—is evidence that someone is not really God’s child. Sin is incompatible with the new nature derived from the new birth. John wants believers to do what is right and thus demonstrate that they are joined to Christ and his righteousness. Those who are children of God do not make a practice of sinning, but this differs from the sort of “sinlessness” that the false teachers claimed (see 1:5-10 and corresponding study notes).