Luther appealed to conscience at the Diet of Worms. Professor Heiko Oberman discusses the matter of conscience for the Reformer. "Appealing to conscience was common medieval practice; appealing to a 'free' conscience that had liberated itself from all bonds would never have occurred to Luther. Nor did he regard 'conscience' identical with the inescapable voice of God in man. Conscience is neither neutral nor autonomous: hotly contested by God and the Devil, it is not the autonomous center of man's personality, it is always guided and is free only once God has freed and 'captured' it. What is new in Luther is the notion of absolute obedience to the Scripture against any authorities; be they popes or councils. The way Luther dislodges the Christian conscience from its individual, immediate proximity to God and integrates it into the obligation to heed reasonable world and historical experience is innovative. Faith is not founded on reason: God's omnipotence transcends reason and the cross of Christ contradicts it. Actions, on the other hand, must be able to stand the test of reason and experience because their sole objective is service to one's neighbor, there no room here for justification or self-sanctfiication. Luther liberated the Christian conscience, liberated it from papal decree and canon law. But he also took it captive through the Word of God and imposed on it the responsibility to render service to the world." Heiko Oberman, 'Luther. Man Between God and the Devil'; Yale University Press, 1989. p. 204