One might say, I would gladly believe if an angel from heaven were to preach to me.  But whoever does not receive the Word for its own sake will never receive it for the sake of the preacher, even if all the angels preached it to him.  He who receives it because of the preacher does not believe in the Word, neither in God through the Word, but he believes the preacher and in the preacher.  Hence the faith of such persons does not last long.  But whoever believes the Word, does not care who the person is that speaks the Word, and neither will he honor the Word for the sake of the person; but on the contrary, he honors the person because of the Word, and always subordinates the person to the Word.  If the preacher perishes, or even falls from the faith and preaches differently, he will forsake the person of the preacher rather than the Word of God.
                                                                                                                                          Martin Luther