1 John 3:4

“Whosoever committeth sin, &c.] This, in connection with what follows, is true of any sin, great or small, but here designs a course of sinning, a wilful, obstinate, persisting in sin: transgresseth also the law; not of man, unless the law of men is founded on, and agrees with the law of God, for sometimes to transgress the laws of men is no sin, and to obey them would be criminal; but the law of God, and that not the ceremonial law, which was now abolished, and therefore to neglect it, or go contrary to it, was not sinful; but the moral law, and every precept of it, which regards love to God or to our neighbour, and which may be transgressed in thought, word, and deed; and he that committeth…”

“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,…”

“Whosoever committeth sin transgresseth also the law - The law of God given to man as a rule of life. The object of the apostle here is to excite them to holiness, and to deter them from committing sin, perhaps in view of the fact stated in 1 John 3:3, that everyone who has the hope of heaven will aim to be holy like the Saviour. To confirm this, he shows them that, as a matter of fact, those who are born of God do lead lives of obedience, 1 John 3:5-10; and this he introduces by showing what is the nature of sin, in the verse before us. The considerations by which he would deter them from indulging in sin are the following: (a)All sin is a violation of the law of God, 1 John 3:4; (b)The very…”

“Whosoever committeth sin - Thereby transgresseth the holy, just, and good law of God, and so sets his authority at nought; for this is implied in the very nature of sin. 1 John 3:5”

“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).”

“committeth: Jo1 3:8, Jo1 3:9; Kg1 8:47; Ch1 10:13; Co2 12:21; Jam 5:15 transgresseth: Num 15:31; Sa1 15:24; Ch2 24:20; Isa 53:8; Dan 9:11; Rom 3:20, Rom 4:15; Jam 2:9-11 for: Jo1 5:17; Rom 7:7-13 1 John 3:5”