"We are saved by faith alone, but the faith that saves is never alone."
I've seen this quoted before, but does anyone know the source for the quote?
This exact quote may not come from Luther though often attributed to him on the internet (I would be interested in seeing it sourced as well), however it does faithfully describe Luther's teaching, as documented below.
MARTIN LUTHER ON FAITH AND WORKS
"We say that justification is effective without works, not that faith is without works. For that faith which lacks fruit is not an efficacious but a feigned faith.. It is one thing that faith justifies without works; it is another thing that faith exists without works." Luther's Works 34: 175-176.
“For it is impossible for him who believes in Christ, as a just Savior, not to love and to do good. If, however, he does not do good nor love, it is sure that faith is not present. Therefore man knows by the fruits what kind of a tree it is, and it is proved by love and deed whether Christ is in him and he believes in Christ. As St. Peter says in 2 Pet. 1, 10: "Wherefore, brethren, give the more diligence to make your calling and election sure; for if ye do these things, ye shall never stumble," that is, if you bravely practice good works you will be sure and cannot doubt that God has called and chosen you.” Sermons of Martin Luther 1:40
“Even those who gladly hear and understand the doctrine of pure faith do not proceed to serve their neighbor, as though they expected to be saved by faith without works: they see not that their faith is not faith, but a shadow of faith…” Sermons of Martin Luther 1:112
“Now let us turn to the second part, the outer man. Here we shall answer all those who, offended by the word “faith” and by all that has been said, now ask, “If faith does all things and is alone sufficient unto righteousness, why then are good works commanded? We will take our ease and do no works and be content with faith.” I answer: not so, you wicked men, not so.” LW 31:357
“…Paul storms against such people as are numbered among but are not Christians in reality. But if you do not have love, he says, your faith is false and empty, even if it is possible for you to move mountains from place to place. Yet, he does not say that men are justified by works or love. For Paul speaks, as it is necessary for us to speak, in human fashion on account of those who boast of faith without works. True faith is not idle. We can, therefore, ascertain and recognize those who have true faith from the effect or from what follows.” Luther, LW 34:183.
“For this reason the Holy Spirit urges works, that they may be witnesses of faith. In those therefore in whom we cannot realize good works, we can immediately say and conclude: they heard of faith, but it did not sink into good soil. For if you continue in pride and lewdness, in greed and anger, and yet talk much of faith, St. Paul will come and say, 1 Cor. 4:20, look here my dear Sir, "the kingdom of God is not in word but in power." It requires life and action, and is not brought about by mere talk.” Sermons of Martin Luther 2.2:341-342
“No, no; faith is a living and an essential thing, which makes a new creature of man, changes his spirit and wholly and completely converts him. It goes to the foundation and there accomplishes a renewal of the entire man; so, if I have previously seen a sinner, I now see in his changed conduct, manner and life, that he believes. So high and great a thing is faith.” Sermons of Martin Luther 2.2:341
“But here we must take to heart the good example of Christ in that he appeals to his works, even as the tree is known by its fruits, thus rebuking all false teachers, the pope, bishops, priests and monks to appear in the future and shield themselves by his name, saying, "We are Christians;" just as the pope is boasting that he is the vicar of Christ. Here we have it stated that where the works are absent, there is also no Christ. Christ is a living, active and fruit-bearing character who does not rest, but works unceasingly wherever he is. Therefore, those bishops and teachers that are not doing the works of Christ, we should avoid and consider as wolves.” Sermons of Martin Luther 1:93
“For thus God has also introduced works, as though he would say: if you believe, then you have the kingdom of heaven; and yet, in order that you may not deceive yourselves, do the works.” Sermons of Martin Luther 2.2:342
“The fruits will not save you nor make you any friends, but they must show and prove that you are saved and are my friends. Therefore mark this well, that faith alone makes us good; but as faith lies concealed within me, and is a great life, a great treasure, therefore the works must come forth and bear witness of the faith, to praise God's grace and condemn the works of men. You must cast your eyes to the earth and humiliate yourself before everyone, that you may also win your neighbor by your services; for this reason God lets you live, otherwise nothing would be better for you than to die and go to heaven.” Sermons of Martin Luther 2.2:342-343
“We must therefore most certainly maintain that where there is no faith there also can be no good works; and conversely, that there is no faith where there are no good works. Therefore faith and good works should be so closely joined together that the essence of the entire Christian life consists in both.” Martin Luther, quoted in Althaus, Paul, The Theology of Martin Luther, p.246, note 99.
“Works are a certain sign, like a seal on a letter, which make me certain that my faith is genuine. As a result if I examine my heart and find that my works are done in love, then I am certain that my faith is genuine. If I forgive, then my forgiving makes me certain that my faith is genuine and assures me and demonstrates my faith to me.” Luther, in Althaus, ibid, p. 247, note 106
“Good works do not make a good man, but a good man does good works; evil works do not make a wicked man, but a wicked man does evil works.” Luther, LW 31:360
“But this birth properly shows its power in times of temptation and death. There it becomes evident who is born again, and who is not. Then the old light, reason, struggles and wrestles and is loath to leave its fancies and desires, is unwilling to consider and resort to the Gospel, and let go its own light. But those who are born again, or are then being born again, spend their lives in peace and obedience to the Gospel, confide in and cling to the witness of John, and let go, their light, life, property, honor, and all they have. Therefore they come to the eternal inheritance, as real children.” Sermons of Martin Luther 1:213
“Faith is a living, restless thing. It cannot be inoperative. We are not saved by works; but if there be no works, there must be something amiss with faith.” Luther, quoted in Brinton, Here I Stand: The Life of Martin Luther, p. 259.
“Moreover, if one's life is bad, it would be strange indeed if he should preach right; he would always have to preach against himself, which he will hardly do without additions and foreign doctrines. In short, he who does not preach the Gospel, identifies himself as one who is sitting neither on Moses' nor on Christ's seat. For this reason you should do neither according to his words nor according to his works, but flee from him as Christ's sheep do, John 10, 4-5: "And the sheep follow him, for they know his voice. And a stranger will they not follow, but flee from him." But if you wish to know what their seat is called, then listen to David: "Blessed is the man that walketh not in the counsel of the wicked, nor standeth in the way of the sinner, nor sitteth in the seat of scoffers, Ps. 1,1. Again: "Shall the throne of wickedness have fellowship with thee, which frameth mischief by statute?" Ps. 94, 20.” Sermons of Martin Luther 1:95
“Thus faith casts itself on God, and breaks forth and becomes certain through its works. When this takes place a person becomes known to me and to other people. For when I thus break forth I spare neither man nor devil, I cast myself down, and will have nothing to do with lofty affairs, and will regard myself as the poorest sinner on earth. This assures me of my, faith. For this is what it says: "This man went down to his house justified." Thus we attribute salvation as the principal thing to faith, and works as the witnesses of faith. They make one so certain that he concludes from the outward life that the faith is genuine.” Sermons of Martin Luther 2.2:341
“This is what I have often said, if faith be true, it will break forth and bear fruit. If the tree is green and good, it will not cease to blossom forth in leaves and fruit. It does this by nature. I need not first command it and say: Look here, tree, bear apples. For if the tree is there and is good, the fruit will follow unbidden. If faith is present works must follow.” Sermons of Martin Luther 2.2:340-341
“Thus we err on both sides in saying, a person must only believe, then he will neglect to do good works and bring forth good fruits. Again, if you preach works, the people immediately comfort themselves and trust in works. Therefore we must walk upon the common path. Faith alone must make us good and save us. But to know whether faith is right and true, you must show it by your works. God cannot endure your dissembling, for this reason he has appointed you a sermon which praises works, which are only witnesses that you believe, and must be performed not thereby to merit anything, but they should be done freely and gratuitously toward our neighbor.” Sermons of Martin Luther 2.2:342