Martin Luther - The words of the law are spoken, not that they might assert the power of the will, but that they might illuminate the blindness of reason, that it might see that its own light is nothing, and that the power of the will is nothing

The third passage is from Moses, (Deut. xxx. 19.) "I have set before thy face life and death, choose what is good, &c."—"What words (says the Diatribe) can be more plain? It leaves to man the liberty of choosing."

I answer: What is more plain, than, that you are blind? How, I pray, does it leave the liberty of choosing? Is it by the expression 'choose'?—Therefore, as Moses saith 'choose,' does it immediately come to pass that they do choose? Then, there is no need of the Spirit. And as you so often repeat and inculcate the same things, I shall be justified in repeating the same things also.—If there be a liberty of choosing, why has the 'probable opinion' said that "Freewill" cannot will good? Can it choose not willing or against its will? But let us listen to the similitude, "It would be ridiculous to say to a man standing in a place where two ways met, Thou seest two roads, go by which thou wilt, when one only was open."

This, as I have before observed, is from the arguments of human reason, which thinks, that a man is mocked by a command impossible: whereas I say, that the man, by this means, is admonished and roused to see his own impotency. True it is, that we are in a place where two ways meet, and that one of them only is open, yea rather neither of them is open. But by the law it is shewn how impossible the one is, that is, to good, unless God freely give His Spirit; and how wide and easy the other is, if God leave us to ourselves. Therefore, it would not be said ridiculously, but with a necessary seriousness, to the man thus standing in a place where two ways meet, 'go by which thou wilt,' if he, being in reality impotent, wished to seem to himself strong, or contended that neither way was hedged up.

Wherefore, the words of the law are spoken, not that they might assert the power of the will, but that they might illuminate the blindness of reason, that it might see that its own light is nothing, and that the power of the will is nothing. "By the law (saith Paul) is the knowledge of sin," (Rom. iii. 20.): he does not say, is the abolition of, or the escape from sin. The whole nature and design of the law is to give knowledge only, and that of nothing else save of sin, but not to discover or communicate any power whatever. For knowledge is not power, nor does it communicate power, but it teaches and shows how great the impotency must there be, where there is no power. And what else can the knowledge of sin be, but the knowledge of our evil and infirmity? For he does not say, by the law comes the knowledge of strength or of good. The whole that the law does, according to the testimony of Paul, is to make known sin. 

And this is the place, where I take occasion to enforce this my general reply: that man, by the words of the law, is admonished and taught what he ought to do, not what he can do: that is, that he is brought to know his sin, but not to believe that he has any strength in himself. Wherefore, friend Erasmus, as often as you throw in my teeth the Words of the law, so often I throw in yours that of Paul, "By the law is the knowledge of sin," not of the power of the will. Heap together, therefore, out of the large Concordances all the imperative words into one chaos, provided that, they be not words of the promise but of the requirement of the law only, and I will immediately declare, that by them is always shewn what men ought to do, not what they can do, or do do. And even common grammarians and every little school-boy in the street knows, that by verbs of the imperative mood, nothing else is signified than that which ought to be done, and that, what is done or can be done, is expressed by verbs of the indicative mood.

Thus, therefore, it comes to pass, that you theologians, are so senseless and so many degrees below even school-boys, that when you have caught hold of one imperative verb you infer an indicative sense, as though what was commanded were immediately and even necessarily done, or possible to be done. But how many slips are there between the cup and the lip! So that, what you command to be done, and is therefore quite possible to be done, is yet never done at all. Such a difference is there, between verbs imperative and verbs indicative, even in the most common and easy things. Whereas you, in these things which are as far above those, as the heavens are above the earth, so quickly make indicatives out of imperatives, that the moment you hear the voice of him commanding, saying, "do," "keep," "choose," you will have, that it is immediately kept, done, chosen, or fulfilled, or, that our powers are able so to do.


- Martin Luther (The Bondage of the Will, Section 56)