In his sermon on the Feast of St. Stephen, in 1515, Luther had spoken of the inward voice in man (“_synteresis_”), which urges him towards what is good and to true happiness, thereby implying the admission of free-will in man. This, he says, is capable of accepting or refusing God’s grace, though he is careful to add that the remnant of vital force represented by the synteresis does not indicate a condition of health nor afford any cause for boasting in God’s sight, the whole state of man being one of corruption; the synteresis, in fact, constitutes a danger to us because it leads us to trust in our own powers (“_voluntas, sapientia_”), so that we are readily induced to regard our restoration by grace as unnecessary. Such confidence in his own powers leads man to place himself on the side of those who crucified Christ, for such a one has a wrong opinion of righteousness and looks on Christ as superfluous, who is the source of righteousness. “Thus it comes about,” he cries, “that grace is most strongly opposed by those who boast most of it”; a paradoxical saying which often occurs in Luther’s early sermons and which plainly owes its origin to his quarrel with the “Little Saints.”[625]
Not here alone, but frequently in the sermons of those days, we hear Luther warning the people against misusing the synteresis. His opposition to man’s natural powers leads him at times so far that he represents the synteresis merely as a vague and practically worthless faculty. It is true he declares that he simply wishes to obviate an irreligious over-esteem of free-will, but he really goes further, now admitting, now rejecting it; his explanations let us see that “here there is an unsolved contradiction in his theology. He fails to explain how the remnant of vital force still in us is to be made use of by Divine grace so as to produce health,” and how “it can be of any importance or worth for the attainment of salvation in the domain of reason and will.” “Is there, then, no right use for the synteresis? Luther not only tells us nothing of this, but the natural consequence of much that he says is an answer to the question in the negative, although it should undoubtedly have been answered in the affirmative.”[626]