The apostle now proceeds to describe the reason why he is writing in this vein to the church of God.  His intention in describing the absolute holiness of God, the necessity of holiness in His people, and the reality of sin and forgiveness, is ultimately to this point: “That ye sin not.”  He is concerned that the children of God manifest an attitude of true righteousness which flows from a renewed heart, which will hate sin in all of its manifestations, and strive after the standard of holiness inculcated in God’s word.  That “walking in the light” of which John wrote in the first chapter necessarily involves separation from sin.  One cannot be walking in the light as God is in the light if he is living a life of abandonment to the lusts of the flesh, and all the powers of sin.  This standard will ultimately separate the believer from the unbeliever.  The unbeliever is not concerned whatsoever that sin is still the guiding principle of his life.  The true Christian, on the other hand, though he knows sin is forgiven for Christ’s sake, still yet mourns when he discovers its pervasive presence in his life, because sin disrupts his fellowship with God, grieves his heavenly Father, and spoils his testimony before the world.

But sin is still a reality that must be admitted and contended with, and John would not have the child of God who discovers sin in himself to be without comfort.  Thus, like a good minister of Jesus Christ, he pours in the balm of the Gospel, telling us, “And if any man sin, we have an advocate with the Father, Jesus Christ the righteous.”  This is a special message intended for the soul comfort of the child of God.  Yes, we find that we sin, much more often than we care to acknowledge.  But the good news is that our sin does not destroy grace, and throw us back under the power of the Devil.  There is an advocate, a lawyer, a defense attorney, as it were, standing before the throne of the just God of heaven and earth, to plead our case.  He does not do like an earthly lawyer, searching the rules and regulations for points of technicality, or any clever excuse by which he might get us off the hook for the punishment we deserve.  No, this great Advocate is too honest to deny that His clients are sinners.  But for all this, He is yet the greatest Defender any man ever had.  His clients, those He represents, surely are guilty and unrighteous, considered in themselves.  But the good news of the Gospel revolves around the doctrine of Substitution, which declares that Jesus Christ stood in our stead, taking our guilt upon Himself, and suffering the punishment for it in His own body upon the tree.  Moreover, as our sin was imputed to Him, that He might bear its punishment, so His righteousness is charged to our account, so that in the record books of heaven we stand “holy as the Holy One.”  By His obedience we are made righteous, says Paul.  Said the same apostle in another place, “He hath made Him to be sin for us, Who knew no sin, that we might be made the righteousness of God in Him.”  This is surely why John ascribes to the Lord Jesus in our passage the title of “the Righteous.”  He wishes us to be reminded that, although we sin and continually must confess before God that we are unrighteous, that we are still received before Him because our acceptance with God is based upon the righteousness of our Advocate, never upon our own personal merit.