What we receive through faith...

The forgiveness of sins and justification is received through faith. The voice of Christ testifies, "So you also, when you have done all that you were commanded, say, 'We are unworthy servants; we have only done what was our duty'" (Luke 17:10). The Fathers teach the same thing. Ambrose says, "It is ordained of God that he who believes in Christ is saved, freely receiving forgiveness of sins, without works, through faith alone.
~BOC, AC, VI, 2-3

God as our schoolmaster...

After God (through the Holy Spirit in Baptism) has kindled and caused a beginning of the true knowledge of God and faith, we should pray to Him without ceasing.  We should ask that through the same Spirit and His grace, by means of the daily exercise of reading and doing God's Word, He would preserve us in faith and His heavenly gifts, strengthen us from day to day, and keep us to the end. For unless God Himself is our schoolmaster, we can study and learn nothing that is acceptable to Him and helpful to ourselves and others.
~BOC, FSD, II, 16

How to think about Baptism...

We must think this way about Baptism and make it profitable for ourselves. So when our sins and conscience oppress us, we strengthen ourselves and take comfort and say, "Nevertheless, I am baptized. And if I am baptized, it is promised to me that I shall be saved and have eternal life, both in soul and body."
~BOC, LC, IV, 44

Only through the Word...

In issues related to the spoken, outward Word, we must firmly hold that God grants His Spirit or grace to no one except through or with the preceding outward Word. This protects us from enthusiasts (i.e., souls who boast that they have the Spirit without and before the Word). They judge Scripture or the spoken Word and explain and stretch it at their pleasure, as Munzer did. Many still do this today, wanting to be sharp judges between the Spirit and the letter and yet they do not know what they are saying.
~BOC, SA, III, VIII, 3

Not merely a knowledge of history...

But the faith that justifies is not merely a knowledge of history.  It is to believe in God's promise.  In this promise, for Christ's sake, forgiveness of sins and justification are freely offered.  And so that no one may suppose that this is mere knowledge, we will add further: it is to want and to receive the offered promise of forgiveness of sins and of justification.
~BOC, AP, AP, IV (II), 48

Justification comes only through the free promise, not ourselves...

Since justification is gained through the free promise, it follows that we cannot justify ourselves. Otherwise, why would there be a need to promise? Since the promise can only be received through faith, the Gospel (which is properly the promise of forgiveness of sins and of justification for Christ's sake) proclaims the righteousness of faith in Christ. The Law does not teach this, nor is this the righteousness of the Law. For the Law demands our works and our perfection. But for Christ's sake, the Gospel freely offers reconciliation to us, who have been vanquished by sin and death. This is received not by works, but by faith alone. This faith does not bring to God confidence in one's own merits, but only confidence in the promise, or the mercy promised in Christ. This special faith (by which an individual believes that for Christ's sake his sins are forgiven him, and that for Christ's sake God is reconciled and sees us favorably) gains forgiveness of sins and justifies us. In repentance, namely, in terrors, this faith comforts and encourages hearts. It regenerates us and brings the Holy Spirit so that we may be able to fulfill God's Law: to love God, truly fear God, truly be confident that God hears prayer, and obey God in all afflictions. This faith puts to death concupiscence and the like. So faith freely receives forgiveness of sins. It sets Christ, the Mediator and Atoning Sacrifice, against God's wrath. It does not present our merits or our love. This faith is the true knowledge of Christ and helps itself to the benefits of Christ. This faith regenerates hearts and comes before the fulfilling of the Law.
~BOC, AP, IV (II), 43-47

The error of believing in only a first grace...

...Christ does not stop being our Mediator after we have been renewed. They err who image that He has merited only a first grace, and that, afterward, we please God and merit eternal life by our fulfilling of the Law. Christ remains Mediator, and we should always be confident that for His sake we have a reconciled God, even though we are unworthy.
~BOC, AP, V (III), 41-42

Clothing your neighbor's weaknesses in your own honor...

Let everyone use his tongue and make it serve for the best of everyone else, to cover up his neighbor's sins and infirmities, excuse them, conceal and garnish them with his own reputation...So also among ourselves should we clothe whatever blemishes and infirmities we find in our neighbor and serve and help him to promote his honor to the best of our ability.
~BOC, LC, I, 285, 287

The Sacraments confirm the promise of the Gospel in every believer...

For this reason, Christ causes the promise of the Gospel not only to be offered in general, but He also seals it through the Sacraments. He attaches them like seals of the promise, and by them He confirms the Gospel to every believer in particular.
~BOC, FSD, XI, 37

A child and pupil of the catechism...

But for myself I [Luther] say this: I am also a doctor and preacher; yes, as a learned and experienced as all the people who have such assumptions and contentment. Yet I act as a child who is being taught the catechism. Every morning--and whenever I have the time--I read and say, word for word, the Ten Commandments, the Creed, the Lord's Prayer, the Psalms, and such. I must still read and study them daily. Yet I cannot master the catechism as I wish. but I must remain a child and pupil of the catechism, and am glad to remain so. (7-8)

God Himself is not ashamed to these these things daily. He knows nothing better to teach. He always keeps teaching the same thing and does not take up anything new or different. All the saints know nothing better or different to learn and cannot finish learning this....Can we finish learning in an hour what God Himself cannot finish teaching? He is engaged in teaching this from the beginning to the end of the world. All prophets, together with all saints, have been busy learning it, have ever remained students, and must continue to be students. (16)

~BOC, LC, LP

Through Word and Sacrament...

Therefore we constantly maintain this point:  God does not want to deal with us in any other way that through the spoken Word and through the Sacraments  Whatever is praised as from the Spirit--without the Word and Sacraments--is the devil himself.  God wanted to appear even to Moses through the bush and spoken Word. No prophet, neither Elijah nor Elisha, received the Spirit without the Ten Commandments or the spoken Word.  John the Baptist was not conceived without the word of Gabriel coming first, nor did he leap in his mother's womb without Mary's voice.  Peter says, "For no prophecy was ever produced by the will of man, but men spoke from God as they were carried along by the Holy Spirit" (2 Peter 1:21).  Without the outward Word, however, they were not holy.  Much less would the Holy Spirit have moved them to speak when they were still unholy.  They were holy, says he, since the Holy Spirit spoke through them.
~BOC, SA, III, IX, 10-13