Second. It is precisely by continuing to keep the Law of God or the Ten Commandments (through the power of the indwelling Holy Spirit) that we are to keep on purifying ourselves. "Whosoever keeps on committing sin, also keeps on transgressing the Law. For sin is the transgression of the Law….
"Little children, let nobody deceive you! He that keeps on doing righteousness, is righteous — even as He is righteous…. Not as Cain, who was of that wicked one, and slew his brother. And why did he slay him? Because his own works were evil, and his brother's righteous….
"Whosoever keeps on hating his brother, is a murderer. And you know that no murderer has eternal life abiding in him…. And whatsoever we ask, we receive from Him — because we continue to keep His Commandments and keep on doing those things that are pleasing in His sight…. And he who continues to keep His Commandments — keeps on dwelling in Him; and He [viz. God through His Holy Spirit Who indwells believers] keeps on dwelling in him."5567
Comments Calvin: "Iniquity or transgression of the Law cannot be overlooked so easily…. He simply wants to teach us that sin comes from contempt of God, and that by sinning the righteousness of the Law is violated…. The perverse life of those who indulge themselves in the licence of sinning, is hateful to God and is unendurable to Him — because it is against His Law….
"Believers," however, "want to submit to God…. They abhor their own vices even in individual offences, and they also compose their life so far as they can to the obedience of the Law."
Third. We are able to purify ourselves and to try to keep God's Commandments precisely because Christ the Son of man lived a pure life. He kept all those Commandments for us; He died for our breach of those Commandments; and He graciously imputes His own human Commandment-keeping to us – as if His Own Commandment-keeping were in fact our very own Commandment-keeping.
"You know that He was manifested to take away our sins. And in Him, is no sin…. Hereby we perceive the love of God — because He laid down His life for us…. Whosoever keeps on committing sin, is of the Devil. For the Devil keeps on sinning from the beginning. For this purpose, the Son of God was manifested — so that He might destroy the works of the Devil."5568
Declares the Apostle John, no doubt here referring principally to Jesus: "He Who keeps on doing righteousness, is righteous…. The Son of God was manifested — so that He might destroy the works of the Devil."5568
Comments Calvin: "The Apostle here teaches that newness of life is shown by good works…. He denies that any[one] belongs to Christ, save he who is righteous and shows himself so by his actions. He now banishes all the others to the fellowship of the Devil, and puts them under his government — so that we may know that there is no middle course, but that Satan exercises his tyranny where Christ's righteousness is not supreme."
Fifth. The true believers have already died to their old evil nature, and they have already been brought back to spiritual life by the implantation of the divine seed of the new nature.5570 Accordingly, they should love one another — even as Jesus loved them.
For "we know that we have passed from death unto life, because we love the brethren…. For this is the message that you heard from the beginning, that we should keep on loving one another…. We ought to lay down our lives for the brethren. Yet whosoever has worldly goods, and sees his brother having need, but shuts up his inward compassion from him — how does the love of God dwell in him?