3:3-10 The sons of God know that their Lord is of purer eyes than to allow any thing unholy and impure to dwell with him. It is the hope of hypocrites, not of the sons of God, that makes allowance for gratifying impure desires and lusts. May we be followers of him as his dear children, thus show our sense of his unspeakable mercy, and express that obedient, grateful, humble mind which becomes us. Sin is the rejecting the Divine law. In him, that is, in Christ, was no sin. All the sinless weaknesses that were consequences of the fall, he took; that is, all those infirmities of mind or body which subject man to suffering, and expose him to temptation. But our moral infirmities, our proneness to sin, he had not. He that abides in Christ, continues not in the practice of sin. Renouncing sin is the great proof of spiritual union with, continuance in, and saving knowledge of the Lord Christ. Beware of self-deceit. He that doeth righteousness is righteous, and to be a follower of Christ, shows an interest by faith in his obedience and sufferings. But a man cannot act like the devil, and at the same time be a disciple of Christ Jesus. Let us not serve or indulge what the Son of God came to destroy. To be born of God is to be inwardly renewed by the power of the Spirit of God. Renewing grace is an abiding principle. Religion is not an art, a matter of dexterity and skill, but a new nature. And the regenerate person cannot sin as he did before he was born of God, and as others do who are not born again. There is that light in his mind, which shows him the evil and malignity of sin. There is that bias upon his heart, which disposes him to loathe and hate sin. There is the spiritual principle that opposes sinful acts. And there is repentance for sin, if committed. It goes against him to sin with forethought. The children of God and the children of the devil have their distinct characters. The seed of the serpent are known by neglect of religion, and by their hating real Christians. He only is righteous before God, as a justified believer, who is taught and disposed to righteousness by the Holy Spirit. In this the children of God are manifest, and the children of the devil. May all professors of the gospel lay these truths to heart, and try themselves by them.

4. Sin is incompatible with birth from God (1Jo 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 1Jo 3:3, "Every man that hath this hope in Him purifieth himself"; and 1Jo 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.