The subsequent quotations are extracted from "The Bondage of the Will," which Luther believed to be his most significant work. The doctrine of faith, as expressed in "De Servo Arbitrio," is deeply grounded in Scripture. Should Luther's thesis be correct, then all religions that are founded on human ability are fundamentally mistaken.
Luther was responding to Erasmus' claims that humans possess a natural moral capacity to obey the gospel. Erasmus assumed that all of God's commands to obey demonstrated that we had the "free-will" or moral ability to fulfill them. Erasmus frequently inquired, "If we are unable to do anything, what is the purpose of all the laws, precepts, threats, and promises in the Bible? All these commandments are worthless if nothing is attributed to the human will. If it is not within the power of every person to keep what is commanded, all the exhortations of Scripture are necessarily meaningless." In response, Luther with great acumen and sarcasm reveals why Erasmus' notion of free will is an erroneous and unscriptural doctrine that ultimately undermines the gospel itself.
The following quotations strike at the heart of the matter: whether Christ alone saves or whether salvation is a synergistic collaboration between man and God. This is still highly relevant for today's Christians, as many of us share Erasmus' unbiblical assumption, which erroneously concludes that any command from God to believe or obey the gospel must imply the moral ability to do so. A large number of evangelicals today make the same unfounded leap and construct an entire theology around it. However, as Dr. Luther said to Erasmus, "When you are finished with all your commands and exhortations... I'll write Ro.3:20 over the top of it all" ("...through the law comes knowledge of sin."). In other words, the commands exist not to reveal our ability but rather our inability, and this moral impotence does not absolve us of our responsibility to obey.
Among the commands is God's universal call to all individuals to repent and believe in the gospel, an impossible act of the will without a supernatural work of the Holy Spirit uniting us to Christ. It is beyond humanity's innate capacity to believe when left to their own native resources. As Jesus himself said of Peter's confession of Him as the Christ, "...flesh and blood has not revealed this to you, but my Father who is in heaven." In other words, only the quickening grace of Jesus Christ, applied by the Spirit, can illuminate God's word in such a way that it opens blind eyes and deaf ears, allowing us to see and know the truth, beauty, and excellence of Jesus Christ. Those who are unregenerate cannot see Christ's excellence and thus have no capacity to love what is spiritual, wholly dependent on God to translate them from darkness to light. The following are some quotes from Dr. Luther on this matter:
"For if man has lost his freedom, and is forced to serve sin, and cannot will good, what conclusion can more justly be drawn concerning him, than that he sins and wills evil necessarily?" Martin Luther BW pg. 149
"...'if thou art willing' is a verb in the subjunctive mood, which asserts nothing...a conditional statement asserts nothing indicatively." "if thou art willing", "if thou hear", "if thou do" declare, not man's ability, but his duty. pg 157
"the commandments are not given inappropriately or pointlessly; but in order that through them the proud, blind man may learn the plague of his impotence, should he try to do as he is commanded." pg. 160
Speaking to Erasmus, "Throughout your treatment you forget that you said that 'free-will' can do nothing without grace, and you prove that 'free-will' can do all things without grace! Your inferences and analogies "For if man has lost his freedom, and is forced to serve sin, and cannot will good, what conclusion can more justly be drawn concerning him, than that he sins and wills evil necessarily?" Martin Luther BW pg. 149
"Even grammarians and schoolboys on street corners know that nothing more is signified by verbs in the imperative mood than what ought to be done, and that what is done or can be done should be expressed by words in the indicative. How is it that you theologians are twice as stupid as schoolboys, in that as soon as you get hold of a single imperative verb you infer an indicative meaning, as though the moment a thing is commanded it is done, or can be done? pg 159
"The passages of Scripture you cite are imperative; and they prove and establish nothing about the ability of man, but only lay down what is and what not to be done." pg 161
"Does it follow from: 'turn ye' that therefore you can turn? Does it follow from "'Love the Lord thy God with all thy heart' (Deut 6.5) that therefore you can love with all your heart? What do arguments of this kind prove, but the 'free-will' does not need the grace of God, but can do all things by its own power...But it does not follow from this that man is converted by his own power, nor do the words say so; they simply say: "if thou wilt turn, telling man what he should do. When he knows it, and sees that he cannot do it, he will ask whence he may find ability to do it..." 164
"By the law is the knowledge of sin' [Rom 3:20], so the word of grace comes only to those who are distressed by a sense of sin and tempted to despair." pg. 168
As to why some are touched by the law and others not, so that some receive and others scorn the offer of grace...[this is the] hidden will of God, Who, according to His own counsel, ordains such persons as He wills to receive and partake of the mercy preached and offered." pg. 169
The "imperative or hypothetical passages, or wishes, by which is signified, not what we can do, or do do...but what we ought to do, and what is required of us, so that our impotence may be made known to us and the knowledge of sin may be given to us." 174
God Incarnate says; 'I would, and thou wouldst not." God Incarnate, I repeat, was sent for this purpose, to will, say, do, suffer and offer to all me, all that is necessary for salvation; albeit He offends many who, being abandoned or hardened by God's secret will of Majesty, do not receive Him thus willing, speaking, doing, and offering. As John says: "The light shineth in the darkness, and the darkness com comprehendeth it not' (John 1.5)
And again: "He came unto his own, and His own received Him not. (v. 11)"The law indicates the impotence of man and the saving power of God..."if any man will come after me': 'he that wills to save his life'; 'if ye love me'; 'if ye shall continue'. In sum, as I have said-let every occurrence of the conjunction 'if', and all imperative verbs, be collected together (so we may help the Diatribe...) [indicating that all commands to believe or follow Christ are conditional, not stating man's ability]
Let all the 'free-will' in the world do all it can with all its strength; it will never give rise to a single instance of ability to avoid being hardened if God does not give the Spirit, or of meriting mercy if it is left to its own strength." p. 202
"omnipotence and foreknowledge of God, I repeat, utterly destroy the doctrine of 'free-will'...doubtless it gives the greatest possible offense to common sense or natural reason, that God, Who is proclaimed as being full of mercy and goodness, and so on, should of His own mere will abandon, harden and damn men, as though He delighted in the sins and great eternal torments of such poor wretches. it seems an iniquitous, cruel, intolerable thought to think of God; and it is this that has been such a stumbling block to so many great men down through the ages. And who would not stumble at it? I have stumbled at it myself more than once, down to the deepest pit of despair, so that I wished I had never been made a man. (That was before I knew how health-giving that despair was, and how close to grace.)" Luther BW pg. 217
"...it was not of the merits of Jacob or Esau, 'but of Him that Calleth that it was said of Sara: the elder shall serve the younger' Paul is discussing whether they attained to what was spoken of them by the power or merits of 'free-will"; and he proves they they did not, but that Jacob attained what Esau did not solely by the grace of "Him that Calleth"224
Now, since on God's own testimony, men are 'flesh', they can savour of nothing but the flesh; therefore 'free-will can avail only to sin. And if, while the Spirit of God is calling and teaching among them, they go from bad to worse, what could they do when left to themselves, without the Spirit of God? Your [Erasmus] observation that Moses is speaking of the men of that age is not to the point at all. The same is true of all men, for all are 'flesh'; as Christ says, 'That which is born of the flesh is flesh' (john 3:6) How grave a defect this is, He Himself there teaches, when he says: 'Except a man be born again, he cannot enter the kingdom of God (v. 5)...I call a man ungodly if he is without the Spirit of God; for Scripture says that the Spirit is given to justify the ungodly. As Christ distinguished the Spirit from the flesh, saying: "that which is born of the flesh is flesh', and adds that which is born of the flesh cannot enter the kingdom of God', it obviously follows that whatever is flesh is ungodly, under God's wrath, and a stranger to His kingdom. And if it is a stranger to God's kingdom and Spirit, it follows of necessity that it is under the kingdom and spirit of Satan. For there is no middle kingdom between the kingdom of God and the Kingdom of Satan, which are ever at war with each other. 241, 253
"I say that man without the grace of God nonetheless remains the general omnipotence of God who effects, and moves and impels all things in a necessary, infallible course; but the effect of man's being carried along is nothing--that is, avails nothing in God's sight, nor is reckoned to be anything but sin." 265
"the Baptist's word means that man can receive nothing unless given him from above; so that free-will is nothing!"
I say that man, before he is renewed into the new creation of the Spirit's kingdom, does and endeavours nothing to prepare himself for that new creation and kingdom, and when he is re-created has does and endeavors nothing towards his perseverance in that kingdom; but the Spirit alone works both blessings in us, regenerating us, and preserving us when regenerate, without ourselves..." 268
"All the passages in the Holy Scriptures that mention assistance are they that do away with "free-will", and these are countless...For grace is needed, and the help of grace is given, because "free-will" can do nothing."270
"I frankly confess that, for myself, even if it could be, I should not want "free-will" to be given me, nor anything to be left in my own hands to enable me to endeavour after salvation; not merely because in face of so many dangers, and adversities and assaults of devils, I could not stand my ground ; but because even were there no dangers. I should still be forced to labour with no guarantee of success.¦ But now that God has taken my salvation out of the control of my own will, and put it under the control of His, and promised to save me, not according to my working or running, but according to His own grace and mercy, I have the comfortable certainty that He is faithful and will not lie to me, and that He is also great and powerful, so that no devils or opposition can break Him or pluck me from Him. Furthermore, I have the comfortable certainty that I please God, not by reason of the merit of my works, but by reason of His merciful favour promised to me; so that, if I work too little, or badly, He does not impute it to me, but with fatherly compassion pardons me and makes me better. This is the glorying of all the saints in their God." - Martin Luther, The Bondage of the Will (Grand Rapids: Revell, 1957), 313-314.