Let us survey briefly the function and use of what is called the “moral law.” Now, so far as I understand it, it consists of three parts.
The first part is this: while it shows God’s righteousness, that is, the righteousness alone acceptable to God, it warns, informs, convicts, and lastly condemns, every man of his own unrighteousness. For man, blinded and drunk with self-love, must be compelled to know and to confess his own feebleness and impurity. If man is not clearly convinced of his own vanity, he is puffed up with insane confidence in his own mental powers, and can never be induced to recognize their slenderness as long as he measures them by a measure of his own choice. But as soon as he begins to compare his powers with the difficulty of the law, he has something to diminish his bravado.
The wickedness and condemnation of us all are sealed by the testimony of the law. Yet this is not done to cause us to fall down in despair or, completely discouraged, to rush headlong over the brink—provided we duly profit by the testimony of the law. It is true that in this way the wicked are terrified, but because of their obstinacy of heart. For the children of God the knowledge of the law should have another purpose. The apostle testifies that we are indeed condemned by the judgment of the law, “so that every mouth may be stopped, and the whole world may be held accountable to God” (Rom. 3:19). This means that, dismissing the stupid opinion of their own strength, [believers] come to realize that they stand and are upheld by God’s hand alone; that, naked and empty-handed, they flee to his mercy, repose entirely in it, hide deep within it, and seize upon it alone for righteousness and merit. For God’s mercy is revealed in Christ to all who seek and wait upon it with true faith. In the precepts of the law, God is but the rewarder of perfect righteousness, which all of us lack, and conversely, the severe judge of evil deeds. But in Christ his face shines, full of grace and gentleness, even upon us poor and unworthy sinners.
The second function of the law is this: at least by fear of punishment to restrain certain men who are untouched by any care for what is just and right unless compelled by hearing the dire threats in the law. But they are restrained, not because their inner mind is stirred or affected, but because, being bridled, so to speak, they keep their hands from outward activity, and hold inside the depravity that otherwise they would wantonly have indulged. Consequently, they are neither better nor more righteous before God. Hindered by fright or shame, they dare neither execute what they have conceived in their minds, nor openly breathe forth the rage of their lust. Still, they do not have hearts disposed to fear and obedience toward God.
But this constrained and forced righteousness is necessary for the public community of men, for whose tranquility the Lord herein provided when He took care that everything be not tumultuously confounded. This would happen if everything were permitted to all men. Nay, even for the children of God, before they are called and while they are destitute of the Spirit of sanctification (Rom. 1:4), so long as they play the wanton in the folly of the flesh, it is profitable for them to undergo this tutelage. While by the dread of divine vengeance they are restrained at least from outward wantonness, with minds yet untamed they progress but slightly for the present, yet become partially broken in by bearing the yoke of righteousness. As a consequence, when they are called, they are not utterly untutored and uninitiated in discipline as if it were something unknown.
The third and principal use, which pertains more closely to the proper purpose of the law, finds its place among believers in whose hearts the Spirit of God already lives and reigns. For even though they have the law written and engraved upon their hearts by the finger of God, that is, have been so moved and quickened through the directing of the Spirit that they long to obey God, they still profit by the law in two ways. Here is the best instrument for them to learn more thoroughly each day the nature of the Lord’s will to which they aspire, and to confirm them in the understanding of it.
Because we need not only teaching but also exhortation, the servant of God will also avail himself of this benefit of the law: by frequent meditation upon it to be aroused to obedience, be strengthened in it. and be drawn back from the slippery path of transgression. In this way the saints must press on: for, however eagerly they may in accordance with the Spirit strive toward God’s righteousness, the listless flesh always so burdens them that they do not proceed with due readiness. The law is to the flesh like a whip to an idle and balky ass, to arouse it to work.
He lays hold not only of the precepts but the accompanying promise of grace, which alone sweetens what is bitter. For what would be less lovable than the law if, with importuning and threatening alone, it troubled souls through fear, and distressed them through fright? David especially shows that in the law he apprehended the Mediator, without whom there is no delight or sweetness.
Adapted from Calvin: Institutes of the Christian Religion (Library of Christian Classics) Volume XX, ed. by John T. McNeill and translated by Ford Lewis Battles. (c) 1960, W. L. Jenkins. Altered and used by permission of Westminister/John Knox Press. First published in 1559.