Absurdity, then, is one of the principal reasons for not taking the words of Moses and Paul literally. But what article of faith does this absurdity sin against? Or who is offended by it? Human Reason is offended, who although she is blind, deaf, stupid, impious, and sacrilegious with regard to all the words and works of God, is brought in at this point as a judge of the words and works of God. On the same line of argument, you will deny all the articles of faith because it is quite the most absurd thing of all, and as Paul says, foolishness to Gentiles and a stumbling block to Jews [I Cor. 1:23], that God should be a man, the son of a virgin, crucified, and seated at the right hand of the Father. It is absurd, I say, to believe such things. Let us therefore invent some tropes with the Arians to prevent Christ from being literally God. Let us invent tropes with the Manichees to prevent his being truly man, and make him a phantom that slipped down through the virgin like a ray of light through a piece of glass, and was crucified. That will be a fine way for us to handle the Scriptures!
But tropes are no use, and there is no avoiding the absurdity. For it remains absurd (as Reason judges) that a God who is just and good should demand of free choice impossible things; that although free choice cannot will good but is in bondage to sin, he should hold this against it; and that when he does not impart the Spirit, he acts no more mildly or mercifully than if he hardened or permitted to be hardened. These things, Reason will repeat, are not the marks of a good and merciful God. They are too far beyond her comprehension, and she cannot bring herself to believe that God is good if he acts in this way, but setting aside faith, she wishes to feel and see and understand how he is good and not cruel. She would, of course, understand if it were said of God that he hardens no one, damns no one, but has mercy on all, saves all, so that with hell abolished and the fear of death removed, there would be no future punishment to be dreaded. That is why she blusters and argues so in the attempt to exonerate God and defend his justice and goodness
The Bondage of the Will
Luther’s Works Vol. 33