A Clean Conscience or a Pure Heart?

I was copying some notes from one journal to another, and came across this quote from Heiko Oberman’s biography of Martin Luther:

“There would be ‘storms sweeping over the conscience’ when faith clung to its hope in God without seeking refuge in good works. At that moment the idol of good conscience would demonstrate its power” (p. 320).

The "idol of good conscience"? How can a good conscience be an idol?  Isn’t Luther going a bit too far here?  What about Paul’s confession that he “always take[s] pains to have a clean conscience toward both God and man” (Acts 24:16), and his exhortations in the Epistles to act on the “grounds of” or “for the sake of” conscience? On the one hand, I see what Luther is saying, and it is breathtakingly liberating. Can it really be true that “saying yes to God means saying no to one’s own conscience," as Luther put it (320)?

It’s a bit ironic that I found an answer in a Puritan prayer, for Oberman likened the Puritans to the monks of Luther’s day, as those who  define their faith by their ability to maintain clear consciences.   It’s possible that Oberman, though an expert on Luther, may have something to learn about the faith of the Puritans. Consider this stanza from “The Spirit as Teacher” from The Valley of Vision.

Apply to my soul the blood of Christ, effectually, continually,
and help me to believe, with conscience
  comforted, that it cleanseth from all sin;
….
Thy office is to teach me to draw near to Christ with a pure heart,
steadfastly persuaded of his love, in the full assurance of faith.
 

If our consciences must be comforted, they can’t be clean.  A clean conscience needs no comforting. Here is a picture of a true believer: of one who comes to the Father with a pure heart, i.e., a troubled conscience, because he knows he is unclean before God. As God the Spirit applies the blood of Christ to his soul, He comforts his conscience.  To have a pure heart, therefore, means to come to Christ without pretense, not as clean, and therefore worthy, but as unclean and in desperate need of the Fountain which flows from the Rock of Ages.

The way is narrow and painful, Luther says, because we must constantly be “torn out” of our conscience – that is, the conscience that “seeks peace in its own holiness.”  May I never presume to think that I can offer a clean conscience to God; may I never step out of the cleansing flow of Christ's blook into the barren desert of self-righteousness!