Opinion is, at best, even the opinion of a true man, but the cloak of his belief, which he may indeed cast to his neighbor, but not with the truth inside it. That remains in his own bosom, the oneness between him and his God. St. Paul knows well — who better? — that by no argument, the best that logic itself can afford, can a man be set right with the truth. He knows that the spiritual perception which comes of hungering contact with the living truth — a perception which is in itself a being born again — can alone be the mediator between a man and the truth. He knows that, even if he could pass his opinion over bodily into the understanding of his neighbor, there would be little or nothing gained from it. For the man’s spiritual condition would be just what it was before.
God must reveal, or nothing is known. And this, through thousands of difficulties occasioned by the man himself, God is ever and always doing his mighty best to accomplish.
— George MacDonald, Your Life in Christ, p. 202-203