Christ makes Himself present in the Lord's Supper not by our faith, but by His almighty power...

It is not our faith that makes the Sacrament, but only the true Word and institution of our almighty God and Savior, Jesus Christ.  His Word always is and remains effective in the Christian Church.  It is not invalidated or rendered ineffective by the worthiness or unworthiness of the minister, nor by the unbelief of the one who receives it.  This is just like the Gospel.  Even though godless hearers do not believe it, the Gospel is and remains nonetheless the true Gospel, only it does not work for salvation in the unbelieving.  So whether those who receive the Sacrament believe or do not believe, Christ remains nonetheless true in His words when He says, "Take, eat; this is My body."  He makes Himself present not by our faith, but by His almighty power.
~BOC, FSD, VII, 89

Worthiness to receive the Lord's Supper does not depend on the greatness or smallness, the weakness or strength of faith, but on Christ's merit...

It must be carefully explained who the unworthy guests of this Supper are.  They are those who go to this Sacrament without true repentance and sorrow for their sins, without true faith and the good intention of amending their lives.  By their unworthy oral eating of Christ's body, they load themselves with damnation (i.e., with temporal and eternal punishments) and become guilty of profaning Christ's body and blood.

Some Christians have a weak faith and are shy, troubled, and heartily terrified because of the great number of their sins.  They think that in their great impurity they are not worthy of this precious treasure and Christ's benefits. They feel their weakness of faith and lament it, and from their hearts desire that they may serve God with stronger, more joyful faith and pure obedience.  These are the true worthy guests for whom this highly venerable Sacrament has been especially instituted and appointed.  For Christ says:

Come to Me, all who labor and are heavy laden, and I will give you rest. (Matthew 11:28)

Those who are well have no need of a physician, but those who are sick. (Matthew 9:12)

[God's] power is made perfect in weakness. (2 Corinthians 12:9)

As for the one who is weak in faith, welcome him; ... for God has welcomed him. (Romans 14:1-3)

Whoever believes in [the Son of God, be it with a strong or with a weak faith] may have eternal life. (John 3:15)

Worthiness does not depend on the greatness or smallness, the weakness or strength of faith.  Instead it depends on Christ's merit, which the distressed father of little faith enjoyed as well as Abraham, Paul, and others who have a joyful and strong faith.
~BOC, FSD, VII, 68-71

The words of the Holy Supper institution cannot and must not be understood other than in their usual, proper, and common meaning...

All the circumstances of the Holy Supper institution testify that these words of our Lord and Savior, Jesus Christ (which in themselves are simple, plain, clear, firm, and beyond doubt), cannot and must not be understood other than in their usual, proper, and common meaning.  For Christ gives this command at the table and at supper.  There is certainly no doubt that He speaks of real, natural bread and of natural wine.  Also, He speaks of oral eating and drinking, so there can be no metaphor (i.e., a change of meaning) in the word bread, as though Christ's body were a spiritual bread or a spiritual food of souls.  Christ is careful not to use metonymy either.  In other words, there is no change of meaning in the word body.  He does not speak about a sign for his body, or about the power of His body and the benefits that He has earned by the sacrifice of His body for us.  Instead, He speaks about His true, essential body (which He delivered into death for us) and about His true, essential blood (which He shed for us on the tree of the cross for the forgiveness of sins.
~BOC, FSD, VII, 48-49

The Holy Spirit carries out both offices together: He slays and makes alive...

The Law indeed says it is God's will and command that we should walk in a new life.  But it does not give the power and ability to begin and to do it.  The Holy Spirit renews the heart.  He is given and received, not through the Law, but through the preaching of the Gospel.  Thereafter, the Holy Spirit uses the Law in order to teach the regenerate from it and to point out and show them in the Ten Commandments what is the "will of God, what is good and acceptable and perfect" (Romans 12:2) in what "good works, which God prepared beforehand, that we should walk" (Ephesians 2:10).  He encourages them  to this.  When they are idle, negligent and rebellious in this mater because of the flesh, He rebukes them through the Law.  So the Spirit carries out both offices together: He slays and makes alive.  He leads into hell and brings up again.  For His office is not only to comfort, but also to rebuke.  For it is written, "when [the Holy Spirit] comes, He will convict the world [which includes also the old Adam] concerning sin and righteousness and judgment" (John 16:8).  Sin is everything that is contrary to God's Law.  St. Paul says, "All Scripture is breathed out by God and profitable for teaching, for reproof" (2 Timothy 3:16), and to rebuke is the Law's special office.  Therefore, as often as believers stumble, they are rebuked by the Holy Spirit from the Law.  By the same Spirit they are raised up and comforted again with the preaching of the Holy Gospel.
~BOC, FSD, VI, 11-14

Renewal, sanctification, love, virtue, and good works cannot and should not be drawn into, or mixed in with, the article of justification before God...

Here belongs also what St. Paul writes in Romans 4:3.  Abraham was justified before God through faith alone, for the sake of the Mediator, without the cooperation of his works.  This was true not only when Abraham was first converted from idolatry and had no good works, but also afterward, when he had been renewed by the Holy Spirit and adorned with many excellent good works.  Paul asked the following question in Romans 4:1-3:  At that time, on what did Abraham's righteousness before God rest for everlasting life, by which he had a gracious God and was pleasing and acceptable to Him?

He answers:

To the one who does not work but trusts Him who justifies the ungodly, his faith is counted as righteousness, just as David also speaks of the blessing of the one to whom God counts righteousness apart from works. (Romans 4:5-6)

Therefore, even though people who are converted and believe in Christ have the beginning of renewal, sanctification, love, virtue, and good works, these cannot and should not be drawn into, or mixed in with, the article of justification before God. This is so the honor due to Christ may remain with Christ the Redeemer and tempted consciences may have a sure consolation, since our new obedience is incomplete and impure.
~BOC, FSD, III, 33-35

The natural free will according to its perverted disposition and nature is strong and active only to do what is displeasing and contrary to God...

In spiritual and divine things the unregenerate person's intellect, heart, and will are utterly unable, by his natural powers, to understand, believe, accept, think, will, begin, effect, do, work, or concur in working anything.  They are entirely dead to what is good.  They are corrupt.  So in mankind's nature since the fall, before regeneration, there is not the least spark of spiritual power remaining or present.  No person can prepare himself for God's grace or accept the grace God offers.  A person is not capable of grace for and of himself.  He cannot apply or accommodate himself to it.  By his own powers he is not able to aid, do, work, or agree in working anything toward his conversion.  He cannot do this fully, halfway, or even in part--not the smallest or most trivial part.  he is sin's servant and the devil's captive, by whom he is moved.  Therefore, the natural free will according to its perverted disposition and nature is strong and active only to do what is displeasing and contrary to God.
~BOC, FSD, II, 7

Original sin makes our heart, feeling, and thought hostile toward God, especially in divine and spiritual things...

Original sin (in human nature) is not just this entire absence of all good in spiritual, divine things.  Original sin is more than the lost image of God in mankind; it is at the same time also a deep, wicked, horrible, fathomless, mysterious, and unspeakable corruption of the entire human nature and all its powers.  It is especially a corruption of the soul's highest, chief powers in the understanding, heart, and will.  So now, since the fall, a person inherits an inborn wicked disposition and inward impurity of heart, an evil lust and tendency.  We all by disposition and nature inherit from Adam a heart, feeling, and thought that are, according to their highest powers and the light of reasons, naturally inclined and disposed directly against God and His chief commandments.  Yes, they are hostile toward God, especially in divine and spiritual things.  For in other respects, regarding natural, outward things that are subject to reason, a person still has power, ability, and to a certain degree understanding--although very much weakened.  All of this, however, has been so infected and contaminated by original sin that it is of no use toward God.
~BOC, FSD, I, 11-12