Luther On: Promises

"God does not deal, nor has he ever dealt, with man otherwise than through a Word of promise. 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; … But God has need of this: that we consider him faithful in his promises [Heb. 10:23], and patiently persist in this belief … [P]romise 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."

Martin Luther, The Babylonian Captivity of the Church