"'But I say, walk by the Spirit, and you will not gratify the desires of the flesh. For the desires of the flesh are against the Spirit, and the desires of the Spirit are against the flesh, for these are opposed to each other, to keep you from doing the things you want to do' ( Gal 5:16-17). All the saints have had and experienced this struggle of the flesh with the Spirit. We, too, experience it. Whoever explores his own conscience, provided that he is not a hypocrite, will surely find that his own situation is just as Paul describes it here, namely, that the flesh struggles against the Spirit. Therefore every saint feels and confesses that his flesh resists the Spirit and that these two are opposed to each other, so that he cannot do what he would want, even though he sweats and labors, it is not possible to do so. If the flesh prevents us from keeping the commandments of God, from loving our neighbors as ourselves, and how much more prevent from loving God with all our heart, etc. Therefore it is impossible for us to be justified by works of the law. The good will is present, which is as it should be (of course, the Spirit Himself resisting the flesh) and it would rather do good, fulfill the law, love God and the neighbor, etc. But the flesh does not obey this will but resists it. Yet God does not impute this sin, for He is propitious to believers for the sake of Christ.

 

It does not follow from this, however, that you should minimize sin or think of it as something trivial because God does not impute it. It is true that He does not impute it, but to whom and on what account? Not to the hardhearted and secure but to those who repent and who apprehend by faith Christ the Propitiator, on whose account all sins are remitted to them and the remnants of sin are not imputed to them. Such people do not minimize sin; they amplify it, because they know that it cannot be washed away by any satisfactions, works, or righteousness, but onlyby the death of Christ. Yet they do not despair because of its enormity but are persuaded that it is forgiven them on account of Christ.

 

I say this to keep anyone from thinking that once faith has been received, sin should not be emphasized. Sin is truly sin, whether you commit it before or after you have come to know Christ. And God always hates sin; absolutely every sin; in fact, so far as the substance of the deed is concerned, every sin is mortal. It is not mortal to the believer on account of Christ the Propitiator, who expiated it by His death. To the person who does not believe in Christ, not only are all his sins mortal, but even his good works are sins, in accordance with the statement: 'Whatever does not proceed from faith is sin' ( Rm 14:23).

 

Therefore it is a pernicious error when the sophists distinguish among sins on the basis of the substance of the deed rather than on the basis of the persons.  Those who believe have the same sin and sin just as great as that of the unbeliever. To the believer, however, it is forgiven and not imputed. To the unbeliever it is retained and imputed. To the former it is venial; to the latter it is mortal, and not because of a difference between the sins, as though the believer's sin were smaller and the unbeliever's larger, but because of a difference between the persons. For the believer knows that his sin has been remitted to him, because Christ handed Himself over for him. Even though he has sin and is sinning, he remains godly. On the other hand, when the unbeliever commits sin, he remains ungodly. These things are truly the wisdom and the consolation of the godly, that even if they have sins and commit sins, yet they know that on account of their faith in Christ these are not imputed to them.