In the "Babylonian Captivity of the Church", Luther decries a few abuses, but nothing as much as that faith is not taken as important or necessary in the Lord's Supper.
First of all, even the very words of promise of the words of institution seem to have been removed from the laity.
But how many are there today who know that the mass is the promise of Christ? I will say nothing of those godless preachers of fables, who teach human ordinances instead of this great promise. And even if they teach these words of Christ, they do not teach them as a promise or testament, neither therefore as a means of obtaining faith.
What we deplore in this captivity is that nowadays they take every precaution that no layman should hear these words of Christ, as if they were too sacred to be delivered to the common people. So mad are we priests that we arrogate to ourselves alone the so-called words of consecration, to be said secretly, yet in such way that they do not profit even us, for we too fail to regard them as promises or as a testament for the strengthening of the faith.
Then he goes on to stress how the words of promise ought to call forth faith.
For God does not deal, nor has he ever dealt, with man otherwise than through a word of promise, as I have said. We in turn cannot deal with God otherwise than through faith in the Word of his promise. He does not desire works, nor has he need of them; rather we deal with men and with ourselves on the basis of works. But God has need of this: that we consider him faithful in his promises (Heb. 10: 23), and patiently persist in this belief, and thus worship him with faith, hope, and love. It is in this way that he obtains his glory among us, since it is not of ourselves who run, but of him who shows mercy (Rom 9:16), promises, and gives, that we have and hold all good things. Behold, this is that true worship and service of God which we ought to perform in the mass. But if the words of promise are not delivered, what exercise of faith can there be? And without faith, who can have hope or love?
... For anyone can easily see that these two, promise and faith, must necessarily go together. For without the promise there is nothing to be believed; while without faith the promise is useless, since it is established and fulfilled through faith. From this everyone will readily gather that the mass, since it is nothing but promise, can be approached and observed only in faith.