By that sort of method I can easily make out that a stone or a log of wood has free choice because it can move both upward and downward, though by its own power only downward, and upward only by the help of another. And as I said above, we shall end with a topsy-turvy use of language and vocabulary by which we say, “No man is all men,” and “Nothing is everything,” making one term refer to the thing itself, and the other to another that may have an incidental or accidental connection with it. That is how after excessive disputing they come in the end to make free choice free “accidentally,” as something that can on occasion be set free by means of some other thing. The question, however, is what free choice is in itself and as regards its substance; and if that question is to be answered, nothing remains of free choice but the empty name, whether they like it or not. The Sophists are at fault in this too, that they attribute to free choice the power of distinguishing between good and evil. They also depreciate regeneration and renewal in the Holy Spirit [Titus 3:5], and make it a purely external reinforcement that never identifies itself with the will, a point on which I shall say more later. But that is enough about your definition.
The Bondage of the Will
Luther’s Works Vol. 33