John Calvin Commentary 1 John 3:4

"Every one that doeth sin doeth also lawlessness; and sin is lawlessness." — 1 John 3:4 (ASV)

Whosoever committeth, or doeth, sin. The Apostle has already shown how ungrateful we must be to God if we make little account of the honor of adoption, by which He, of His own goodwill, graciously acts first for us, and if we do not, at least, show Him love in return. He, at the same time, introduced this admonition: that our love should not be diminished because the promised happiness is delayed. But now, as people are accustomed to indulge themselves more than they should in evil, he reproves this perverse indulgence, declaring that all those who sin are wicked and transgressors of the law. For it is probable that there were then those who downplayed their vices with this kind of flattery: “It is no wonder if we sin, because we are human; but there is a great difference between sin and iniquity.”

The Apostle now dispels this frivolous excuse when he defines sin as a transgression of the divine law, for his object was to produce hatred and horror of sin. The word sin seems light to some, but iniquity or transgression of the law cannot appear to be so easily forgiven. But the Apostle does not make sins equal by charging all who sin with iniquity; rather, he simply means to teach us that sin arises from a contempt of God, and that by sinning, the law is violated. Therefore, this doctrine of John has nothing in common with the delirious paradoxes of the Stoics.

Besides, to sin here does not mean to offend in some instances; nor is the word sin to be taken for every fault or wrong a person may commit; but he calls that sin when people with their whole heart run into evil, nor does he consider people to sin, except those who are given up to sin. For the faithful, who are still tempted by the lusts of the flesh, are not to be considered guilty of iniquity, though they are not pure or free from sin. But as sin does not reign in them, John says that they do not sin, as I will shortly explain more fully.

The meaning of the passage is that the perverse life of those who indulge themselves in the liberty of sinning is hateful to God, and He cannot tolerate it, because it is contrary to His Law. It does not therefore follow, nor can it therefore be inferred, that the faithful are iniquitous, because they desire to obey God, abhor their own vices in every instance, and also conform their own lives, as much as is in their power, according to the law. But when there is a deliberate purpose to sin, or a continued course in sin, then the law is transgressed.