Luther's The Bondage of the Will has turned out to be a captivating read. One aspect of it which I find somewhat amazing is that it seems Luther speaks to the situation in the Church today no less than he did 500 years ago. In the section below Luther reprimands Erasmus for minimizing the importance of assertions or belief in objective statements of truth from God's Word. Erasmus' goal in downplaying the importance of these assertions seems to have been, to some degree, a desire for unity among Christians - a desire for unity between Luther and the pope. But ostensibly good ends (unity among Christians) do not justify evil means (compromising on truth). I found this reminder from Luther very timely as this lack of respect for right assertions, that is, right doctrine (orthodoxy), seems rampant within Evangelicalism today. As in Luther's day, minimizing the importance of right doctrine today is often done in the name of unity.
To take no pleasure in assertions is not the mark of a Christian heart; indeed, one must delight in assertions to be a Christian at all. (Now, lest we be misled by words, let me say here that by 'assertion' I mean staunchly holding your ground, stating your position, confessing it, defending it and persevering in it unvanquished. I do not think that the term has any other meaning, either in classical authors or in present-day usage. And I am talking about the assertion of what has been delivered to us from above in the Sacred Scriptures.) . . .. . . Away, now, with Skeptics and Academics from the company of us Christians; let us have men who will assert, men twice as inflexible as very Stoics! Take the Apostle Paul - how often does he call for that 'full assurance' (Col. 2:2, 1 Thess. 1:5; Heb. 6:11, 10:22) which is, simply, an assertion of conscience, of the highest degree of certainty and conviction. In Rom. 10 he calls it 'confession' - 'with the mouth confession is made unto salvation' (v. 10). Christ says, 'Whosoever confesseth me before men, him will I confess before my Father' (Matt. 10:32). Peter commands us to give a reason for the hope that is in us (1 Pet. 3:15). And what need is there of a multitude of proofs? Nothing is more familiar or characteristic among Christians than assertion. Take away assertions, and you take away Christianity. . .. . . The Holy Spirit is no Skeptic, and the things He has written in our hearts are not doubts or opinions, but assertions - surer and more certain than sense and life itself.-Martin Luther, The Bondage of the Will