Here are a couple of goodies by Luther on the old stalwart of a doctrine: justification by faith alone. Much maligned by many, it remains the only plank of hope in crazy, sin sick world filled with crazy, sin sick people. It is our only hope as Christians as we constantly try to fool ourselves that we are really not so bad after all.
From this anyone can clearly see how a Christian is free from all things and over all things so that he needs no works to make him righteous and save him, since faith alone abundantly confers all these things. Should he grow so foolish, however, as to presume to become righteous, free, saved, and a Christian by means of some good work, he would instantly lose faith and all its benefits, a foolishness aptly illustrated in the fable of the dog who runs along a stream with a piece of meat in his mouth and, deceived by the reflection of the meat in the water, opens bis mouth to snap at it and so loses both the meat and the reflection.
Freedom of the Christian, 356. AE, vol. 31.
For God will accept no other mediation and no other mediator than his only Son, whom the Father sent into the world and whom he caused to shed his blood for the sole purpose that he might thereby obtain for us the treasure of faith. That, briefly, is the sum total of the gospel that we preach.
And if anyone seeks another way to be freed from his sins and stand before God, he blasphemes and insults God and accuses him of lying, as if he had let his Son shed his blood in vain and his death had accomplished nothing and was of no importance.
For this is what God insists on and nothing else, that no one shall stand
before him except by that innocent blood alone. And if anyone undertakes some other method, such as his works or order or station in life, he shall belong to the devil much more than anyone else. For it is a very serious matter with God and he will have no jest made of it, because for this purpose he gave his Son to die. For that reason we know and have no other sacrifice than that which he made on the cross, on which he died once for all as the, Epistle to the Hebrews [9:12, 26] says, and thereby put away the sins of all men and also made us holy for eternity.
The Abomination of the Secret Mass, 312-313, AE. vol. 36.