The debate between Luther and Erasmus was basically about to what degree, if any, a sinner can freely prepare him/herself for the reception of divine grace. When rejecting the bull of Pope Leo X, Luther had used an exaggerating deterministic or necessitarian theological language which alarmed Erasmus. Erasmus concentrated on the application of God’s grace into the human situation “from below”; Luther, on the contrary, focused on the theocentric nature of grace “from above.” Erasmus promoted the commonly accepted rational view of Late Medieval Catholic soteriology: “to those who do what they can God does not deny his grace,” God’s justice requires that he necessarily grant grace to anyone who freely prepares him/herself to receive it, while Luther spoke the language of Biblical realism: Although human will is free in relation to the natural world, the human being is captivated by the overwhelming power of unfaith, sin, and Satan, being incapable of changing his/her ultimate psychic orientation. In his criticism Luther rehabilitated Augustine’s teaching on the radical limits of human freedom and on the Pneumatological dynamism of divine grace, the view neglected in Medieval theology. Research on Luther’s The Bondage of the Will has not recognized the strong Pneumatological and Trinitarian accent of his theology. Instead, the contradiction between Luther and Erasmus has been explained in philosophical terms such as free will, determinism, necessity, and predestination; this has not revealed the true nature of the profoundly theological conflict between the two “forms of Christianity.” The work at hand makes critical comments on Luther research of the last hundred years and launches the task of a detailed and thorough systematic-theological analysis of the major treatise of Luther.