I wish you to notice the connection in which these words stand. The connection is this: "If we walk in the light as He is in the light, we have fellowship one with another, and the blood of Jesus Christ His Son cleanseth us from all sin. If we say that we have no sin, . . . the truth is not in us. But if we confess our sins, He is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness."
Now if the "we" here means the persons cleansed, just spoken of when it says, "The blood of Jesus Christ cleanseth us from all sin," we must convict this inspired writer of a manifest contradiction in affirming that the same persons are cleansed from all sin and yet are still living in sin. It is very much like saying that vaccination is a prophylactic against small-pox, but if any one tries it, and proves it is so, he is a liar. Or quinine is a specific against fevers, especially malarial fevers, but if any one tries it, and is cured, and makes declaration of the fact, it is false. That is the absurdity to which John is reduced by that kind of exposition.
He is addressing a class of men who believe there is no sin in their souls. This is one fallacy of the gnostics, they believe that these two principles of good and evil exist in the world, run on parallel lines, and never touch. The sin principle they believe to be only in the body, the envelope of the soul, never staining the soul itself. The sin is all laid off upon the body, and is only a seeming sin; the soul is not a sinner, and is unpolluted. A person may appear to be a great sinner, mixed up strangely with sin, but he is not. And the figure they used was this: You may cast a gold ring into a hog-pen, and have it trodden down in the filth there, and it remains gold still; the filth does not really touch or render the gold impure. And so the gold of their souls remained pure and holy, though their bodies were full of sin, of drunkenness, of lust, of all iniquity.
That is the class of men John had to deal with, a class that sprang up in the age of the apostle, and to them he says, If you say you have no sin that needs the atonement, that needs the cleansing blood of the Lord Jesus Christ, you utter a falsehood, and the truth is not in you. But if you own up and make a clean breast of it, and confess you are a sinner before God, and flee to the great fountain of cleansing, then what follows? We shall see: "If we confess our sins, He is faithful and just to forgive us our sins," and to go a step further, not only to forgive the sins that have reference to the past, but to cleanse the nature from the sin principle which is in it, "from all unrighteousness." I think this exposition renders John a self-consistent writer, eliminates all contradiction from the passage, and, in view of the gnostic errors prevailing at that time, is the sound exposition of that text. "If we say we have not sinned, we make Him a liar, and His word is not in us," This is true of every one who has committed one willful sin. He needs the atoning blood of Christ for his pardon.
There were two classes of gnostics, one of which conceived the principles of good and evil to run parallel and never touch, while the other class believed that good and evil intermingled, interpenetrated; — the evil in the body staining the spirit, and that, therefore, so long as the spirit was in the body, entire sanctification was an impossibility. I throw myself back upon St. Paul, who flatly contradicts that doctrine in his wonderful prayer in Thessalonians, fifth chapter, twenty-third verse: "And the very God of peace sanctify you wholly; and I pray God your whole spirit, and soul, and body be preserved blameless unto the coming of our Lord Jesus Christ." St. Paul here expresses the idea that the soul may be sanctified wholly, and the body may be sanctified entirely. The soul is a kind of border-land between pure spirit and the body, according to metaphysicians. There is another passage of St. Paul's expressing the same idea, and that is in second Corinthians, seventh chapter and first verse: "Having therefore these promises, dearly beloved, let us cleanse ourselves from all filthiness of the flesh and spirit, perfecting holiness in the fear of God." "Filthiness of the flesh" means all sins that find expression through the flesh, gluttony, drunkenness, the narcotic appetite, — I hope I shall not wound anyone, — sluggishness, pampering of the body, — you can carry out the thought, — all sins that find expression through the body, all gratification of unlawful appetite. But St. Paul has not got through yet: "Having therefore these promises, dearly beloved, let us cleanse ourselves from all filthiness of the flesh and spirit," the other element, the spirit. I suppose a pure spirit, that is a disembodied spirit, free from all entanglement of matter, as we conceive Satan to be, may be guilty of very many sins. Satan is a great unbeliever to begin with, full of pride and malignity and disobedience, and all forms of sin that may dwell in a disembodied spirit. So man's spirit is all polluted by sin, but God can cleanse it completely.
— Mile-Stone Papers, Part 1, Chapter 11.