The Sacraments awaken and confirm faith...

They [the Sacraments] were instituted to awaken and confirm faith in those who use them.  Therefore, we must use the Sacraments in such a way that faith, which believes the promises offered and set forth through the Sacraments, is increased.
~BOC, AC, XIII, 2

The Law is not kept without Christ...

Therefore, in all our praising of works and in the preaching of the Law, let us keep this rule: The Law is not kept without Christ.  As He Himself has said, "Apart from Me you can do nothing" (John 15:5).  Likewise, "Without faith it is impossible to please [God]" (Hebrews 11:6).  For it is very certain that the doctrine of the Law is not intended to remove the Gospel and to remove Christ as the Atoning Sacrifice.  Let the Pharisees, our adversaries, be cursed.  They interpret the Law to assign Christ's glory to works.  (In other words, they say works are an atoning sacrifice, that they merit the forgiveness of sins.)  Works are always rightly praised in this way: they are pleasing because of faith.  For works do not please without Christ as the Atoning Sacrifice. "Through Him we have also obtained access [to God]" (Romans 5:2), not by works without Christ as Mediator.  Therefore, when it is said in Matthew 19:17, "If you would enter life, keep the commandments," we must believe that without Christ the commandments are not kept and cannot please.
~BOC, AP, V(III), 148-149

On speculating about God's eternal foreknowledge and election...

Our curiosity always has greater pleasure in giving itself to these matters than with what God has revealed to us about this matter in His Word.  We cannot harmonize God's revelation with our reason, which we have not been commanded to do anyway.

There is no doubt that God foresaw before the time of the world, and still knows, exactly, which people who are called will believe and which will not believe.  He also knows which of the converted will persevere and which will not persevere.  He knows which will return after a fall and which will fall into stubbornness.  He also knows the number of how many there are on either side.  Beyond all doubt this is perfectly known to God.  However, God has reserved this mystery for His wisdom.  He has revealed nothing to us about it in His Word, much less commanded us to investigate it with our thoughts.  Instead, He has seriously discouraged us from that.  Therefore, we should not reason in our thoughts, draw conclusions, or inquire curiously into these matters, but we should cling to His revealed Word, to which He points us.

~BOC, FSD, XI, 53-55

The giving of Jesus Christ and the Holy Spirit...

Christ was given for this purpose, that forgiveness of sins might be bestowed on us for His sake.  He was also given so that the Holy Spirit might bring forth in us new and eternal life and eternal righteousness.  Therefore, the Law cannot truly be kept unless the Holy Spirit is received through faith.  So Paul says that the Law is established through faith, and not made useless, because the Law can only be kept when the Holy Spirit is given.
~BOC, AP, V (III), 11-12

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