But the doctrine of justification is this, that we are pronounced righteous and are saved solely by faith in Christ, and without works…  (Luther: Lectures on Galatians, from Luther's Works, Vol. 26, page 223)

The acceptance with which God receives us into his favour as if we were righteous…  (Calvin: Institutes of Christian Religion 3.11.2)

God justifies not only by pardoning but by regenerating, he asks, whether he leaves those whom he justifies as they were by nature, making no change upon their vices?  The answer is very easy: as Christ cannot be divided into parts, so the two things, justification and sanctification, which we perceive to be united together in him, are inseparable.  ( Calvin: Institutes of Christian Religion 3.11.6 )

Since we are justified, through God's imputation, therefore by faith, not by works…  ( Luther: Lectures on Romans, from Luther's Works Vol. 25, page 43 )

You should deal first with the center of our teaching and fix in the people's minds what [they must know] about our justification; that is, that it is an extrinsic righteousness – indeed it is Christ's.  ( Luther: Letters II, from Luther's Works Vol. 49, page 263 )

Justification is by faith alone, but not by faith that is alone.  Saving faith is not a "lonely" faith, having no works following as a companion.  ( Sproul, Faith Alone, page 156 )

In plain words, faith alone justifies a person, Romans 3–5.  After a man has been justified by faith, it is inevitable that the fruits of justification follow, since a good tree is not able not to bear good fruits, and a bad tree bad fruits, as Christ says (Matthew 7:18).  (Luther: Minor Prophets II: Jonah and Habakkuk, from Luther's Works Vol. 19, page 23)

I reply to the argument, then, that our obedience is necessary for salvation.  It is, therefore, a partial cause of our justification.  Many things are necessary which are not a cause and do not justify, as for instance the earth is necessary, and yet it does not justify.  If man the sinner wants to be saved, he must necessarily be present, just as he asserts that I must also be present.  What Augustine says is true, "He who has created you without you will not save you without you."  Works are necessary to salvation, but they do not cause salvation, because faith alone gives life.  On account of the hypocrites we must say that good works are necessary to salvation.  It is necessary to work.  Nevertheless, it does not follow that works save on that account, unless we understand necessity very clearly as the necessity that there must be an inward and outward salvation or righteousness.  Works save outwardly, that is, they show evidence that we are righteous and that there is faith in a man which saves inwardly, as Paul says, "Man believes with his heart and so is justified, and he confesses with his lips and so is saved" [Romans 10:10].  Outward salvation shows faith to be present, just as fruit shows a tree to be good.  (Luther: The Disputation Concerning Justification, from Luther's Works Vol. 34, page 135)

On the other hand, the subject of justification was discussed more cursorily, because it seemed of more consequence first to explain that the faith by which alone, through the mercy of God, we obtain free justification, is not destitute of good works;  (Calvin: Institutes of Christian Religion 3.11.1 [underlined emphasis added])

Man, by his fall into a state of sin, has wholly lost all ability of will to any spiritual good accompanying salvation: so as, a natural man, being altogether averse from that good, and dead in sin, is not able, by his own strength, to convert himself, or to prepare himself thereunto.  (Westminster Confession of Faith IX.3.)

As for those wicked and ungodly men whom God, as a righteous Judge, for former sins, does blind and harden, from them He not only withholds His grace whereby they might have been enlightened in their understandings, and wrought upon in their heart; but sometimes also withdraws the gifts which they had, and exposes them to such objects as their corruption makes occasion of sin; and, withal, gives them over to their own lusts, the temptations of the world, and the power of Satan, whereby it comes to pass that they harden themselves, even under those means which God uses for the softening of others.  ( Westminster Confession of Faith V.6 )

By the decree of God, for the manifestation of His glory, some men and angels are predestinated unto everlasting life; and others foreordained to everlasting death.  ( Westminster Confession of Faith III.3 )

They, whom God has accepted in His Beloved, effectually called, and sanctified by His Spirit, can neither totally nor finally fall away from the state of grace, but shall certainly persevere therein to the end, and be eternally saved.  (Westminster Confessions of Faith XVII.1)

Baptism is recorded in the last chapter of Mark: "Go into all the world and preach the gospel to the whole creation.  He who believes and is baptized will be saved; but he who does not believe will be condemned" (Mark 16:15-16).  Even if a person is baptized but is without faith, he is lost.  But we shall at this time omit discussion of that which serves us in disputation and controversy with the adversaries.  In connection with baptism the words themselves, which are recorded here, must be understood.  These every person must know.  In the first place, note the command of God, which is very stern when he says: "He who believes and is baptized will be saved; but he who does not believe will be condemned" (Mark 16:16).  This is a strict command; if a person wants to be saved, let him be baptized; otherwise he is in God's disfavor.  ( Luther: Sermons I, from Luther's Works Vol. 51, page 188 [underlined emphasis added] )