But the papacy is, for Luther, not simply a tyranny which can be described, as a liberal historian might describe it, in terms of the corrupting influence of power. Its tyranny is of a unique kind, for which there can only be one category, the demonic, biblical category of anti-Christ. By its entanglement with law and politics, the papacy has brought the souls of men and women into bondage, has confused, disastrously, the law and gospel, and has become the antithesis of the Word of God which comes to free and liberate men’s souls. Thus, he cannot regard the papacy simply as a corrupt institution, as did the medieval moralists and the heretics. In Luther’s later writings, the papacy is included along with the law, sin, and death among the tyrants who beset the Christians and is part of a view of salvation which demands an apocalyptic interpretation of history.
From: The Righteousness of God: Luther Studies: the Birkbeck Lectures for 1947 by Gordon Rupp (London: Hodder and Stoughton, 1953), p. 13.