Erasmus of Rotterdam was popularly known as the prince of the humanists. His contemporaries and modern scholars alike have recognized his influence on 16th century reformers as well as political and religious leaders of the same era. It is not an exaggeration to say that Erasmus’ contributions to the principles of 16th century humanism and Christianity, in general, are without peer.

However, the success of Erasmus’ writings and popularity also brought opposition and enemies. As a direct result of his emphasis on public virtue and moral responsibility, Erasmus was fond of satirizing those in authority he saw as providing an immoral example for what he referred to as the “common herd,” especially the Pope and emperor. Consequently, by 1524, Erasmus could have claimed as many detractors amongst the clergy and faculties of Europe as Luther.

So it was when Erasmus published De libero arbitrio he was, despite his aversion to public quarrels, thrust into open contention against Luther. He did not seek open public debate with Luther, but with the number of voices who questioned Erasmus’ loyalties to the Roman curia and emperor rising in volume, Erasmus was compelled to publish something in his own defense. As Erasmus wrote to fellow humanist Willibald Pirkheimer in 1522:

The ill will of certain people has so swamped me in hate that anything I try is useless... the Lutherans threaten [me] openly with their abusive writings, and the emperor is as good as convinced that I am the source and head of the whole Luther tumult. So I run into greatest danger on both sides while having made them both indebted to me.

Erasmus believed there was little else he could do. Opponents (such as the papal nuncio, Aleander) were unremitting in their accusations, aligning Erasmus with Luther and the other Wittenbergers. Erasmus noted on another occasion, “I had intended to write something, not against Luther but for concord. But I now see both parties [are] so in heat, that it is better to remain silent.” And yet, “a few lines further on, a theme occurred to him that he would choose for the debate: the freedom of the will.”

The only way out of his troubles was to begin putting distance between himself and the views of Luther. Erasmus had initially sought a way to address his concerns without publicly challenging Luther and to do it in such a way that his opponents would be mollified. However, Erasmus’ initial plan for writing three dialogues describing the issues standing between him and Luther never reached fruition. Instead, private letters – those of Luther and Erasmus – were acquired by publishers and distributed. The result was that Erasmus grew more and more upset by Luther’s apparent lack of respect. As Erasmus learned from John Oecolampadius, Luther had even included Erasmus in his lectures on Isaiah, saying:

What Erasmus knows about judging spiritual questions, or what he pretends to know, is borne out amply in his writings, from the first to the latest. I am not insensitive to his assorted barbs, but while outwardly he acts as though he is not my foe, I do the same, as though I did not understand his cunning – although I catch on better than he realizes. He has delivered in the field to which he was called; he has introduced us to languages and steered us away from the godless studies (of scholasticism). Perhaps, like Moses, he will die in the plains of Moab, for he is unlikely to advance to the higher studies (which cultivate the fear of God)… He has done enough in exposing the evil. (So far as I can see) he is unable to show us the good and to lead us into the promised land.

Erasmus also complained to the Swiss reformer, Ulrich Zwingli, “I am not much to be trusted in matters concerning the Spirit. I don’t know what that should mean... I’d like to learn from you, learned Zwingli, what kind of a spirit that is.” In another letter to Zwingli, written in 1523, Erasmus further complained that Luther spoke in “‘riddles” and ‘paradoxes’, listing among them the view that, ‘free will’ is an ‘empty word’.”

What followed was Erasmus’ decision to publish the tract De libero arbitrio. This was not only calculated to disentangle himself from accusations of false teaching but to also put distance between himself and comparisons to Luther.

Erasmus' treatise was well received by the Pope and emperor. Now, with his loyalties secured, Erasmus was positioned to strike at Luther. Writing to Duke George of Saxony, for example, Erasmus noted that he saw, “Luther as one of the long lines of those used by God – like Pharaoh, the Philistines, Nebuchadnezzar, and the Romans – to chastise the chosen people for their own good, a necessary scourge.”

Of course, Luther was aware of these criticisms while publishing De servo arbitrio (The Captivation of the Will) in December of 1525. He – for his part – was convinced Erasmus had become, “an enemy of God and the Christian religion, an Epicurian and a serpent, and he was not afraid to say so.”

His response to Erasmus was not meant to be a polite contribution to an academic duel. His treatise, “deals directly and uncompromisingly with the basic principles of religion – the nature of God and the nature of men – and as such led to the production of one of the enduring monuments of evangelical doctrine, a masterpiece in the realm of polemics, dogmatics, and exegesis..." (J.L Packer translation of Martin Luther’s The Bondage of the Will, pg.40).

The debate that emerged between Luther and Erasmus during 1525 was not just a dispute regarding the role of the human will in salvation. At issue was an argument about the basic principles of true theology and true knowledge of God.