One of Paul’s most important teachings… is the doctrine of what we call “justification by faith”.  It frequently appears to the non-Christian mind that this is an immoral or at least unmoral doctrine.  Paul appears to be saying that a man is justified before God, not by his goodness or badness, not by his good deeds or bad deeds, but by believing in a certain doctrine of Atonement.  Of course, when we come to examine the matter more closely, we can see that there is nothing unmoral in this teaching at all.  For if “faith” means using a God-given faculty to apprehend the unseen divine order, and means, moreover, involving oneself in that order by personal commitment, we can at once see how different that is from merely accepting a certain view of Christian redemption… That which man in every religion, every century, every country, was powerless to affect, God has achieved by the devastating humility of His action and suffering in Jesus Christ.  Now, accepting such an action as a fait accompli is only possible by this perceptive faculty of “faith”.  It requires not merely intellectual assent but a shifting of personal trust from the achievements of the self to the completely undeserved action of God.  To accept this teaching by mind and heart does, indeed, require a metanoia [“transformation”], a revolution in the outlook of both heart and mind.

… J. B. Phillips (1906-1982),
New Testament Christianity [1956]