If you mix faith and works, if you say, “Yes, I have to have faith in what Jesus has done for me, but I also have to add this or this or this, or I’m not saved,” then you’re saying that what actually saves you is not what Jesus has done, but what you add. It makes you your own savior.
This illustration might help. Mr. A asked Mr. B to make him a wooden cabinet because Mr. B was a great cabinetmaker. Mr. B and Mr. A were friends, and therefore Mr. B said, “Well, I better make this really good . . . perfect.” So he worked and worked and worked on the cabinet till he got it to the place where it had been buffed and polished to perfection. He brought Mr. A into the workshop to see it, and Mr. A picked up a piece of sandpaper and said, “Let me just add one little stroke.” Mr. B said, “No! It is finished. It’s perfect. And there’s no way to add to it without subtracting from it.”
It’s the same with Jesus Christ’s work. Because when Jesus died, he said, “It is finished.” There is nothing else to add to it. It’s perfect. And if you add to it, you subtract from it. If you say, “He did this but I have to add this,” anything you add becomes the real basis of your salvation and makes you your own savior.
The Protestant Reformers made strong biblical arguments that you cannot mix faith and works, that justification and righteousness and salvation must be through faith alone. I won’t make any more of those arguments; I’ll just say this: Personally, I couldn’t live if that wasn’t the case. I don’t have any hope unless I can get up every day and stand on the bedrock knowledge that
My hope is built on nothing less
than Jesus’ blood and righteousness.
I dare not trust the sweetest frame
but wholly lean on Jesus’ name.
That’s my only hope.
We maintain that of whatever kind a man’s work may be, he is regarded as righteous before God simply on the ground of gratuitous mercy; because God, without any respect to works, freely adopts him in Christ, by imputing the righteousness of Christ to him as if it were his own. This we call the righteousness of faith, that is when a man, empty and drained of all confidence in works, feels convinced that the only ground of his acceptance with God is a righteousness which is wanting in himself, and is borrowed from Christ. The point on which the world goes astray (for this error has prevailed in almost every age), is in imagining that man, however partially defective he may be, still in some degree merits the favour of God by works. . . . God reconciles us to himself, from regard not to our works but to Christ alone, and by gratuitous adoption makes us his own children instead of children of wrath. So long as God regards our works, he finds no reason why he ought to love us. Wherefore it is necessary that he should bury our sins, impute to us the obedience of Christ which alone can stand his scrutiny, and adopt us as righteous through his merits. This is the clear and uniform doctrine of Scripture, “witnessed,” as Paul says, “by the law and the prophets” (Rom. 3:21).