8 Everyone who commits sin is a child of the devil; for the devil has been sinning from the beginning. The Son of God was revealed for this purpose, to destroy the works of the devil. 9 Those who have been born of God do not sin, because God's seed abides in them; they cannot sin, because they have been born of God. 10 The children of God and the children of the devil are revealed in this way: all who do not do what is right are not from God, nor are those who do not love their brothers and sisters.
11 For this is the message you have heard from the beginning, that we should love one another. 12 We must not be like Cain who was from the evil one and murdered his brother. And why did he murder him? Because his own deeds were evil and his brother's righteous.
Matthew Henry's Commentary on 1 John 3:8-12
Commentary on 1 John 3:3-10
(Read 1 John 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.
Commentary on 1 John 3:11-15
(Read 1 John 3:11-15)
We should love the Lord Jesus, value his love, and therefore love all our brethren in Christ. This love is the special fruit of our faith, and a certain sign of our being born again. But none who rightly know the heart of man, can wonder at the contempt and enmity of ungodly people against the children of God. We know that we are passed from death to life: we may know it by the evidences of our faith in Christ, of which love to our brethren is one. It is not zeal for a party in the common religion, or affection for those who are of the same name and sentiments with ourselves. The life of grace in the heart of a regenerate person, is the beginning and first principle of a life of glory, whereof they must be destitute who hate their brother in their hearts.