Grace, mercy and peace be unto you from God, our Father, and from our Lord and Savior Jesus Christ. Amen.

Our text is the Epistle reading from Hebrews chapter nine.

"But when Christ appeared as a high priest of the good things that have come, then through the greater and more perfect tent (not made with hands, that is, not of this creation) he entered once for all into the holy places, not by means of the blood of goats and calves but by means of his own blood, thus securing an eternal redemption. For if the blood of goats and bulls, and the sprinkling of defiled persons with the ashes of a heifer, sanctify for the purification of the flesh, how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God. Therefore he is the mediator of a new covenant, so that those who are called may receive the promised eternal inheritance, since a death has occurred that redeems them from the transgressions committed under the first covenant." So far our text.

"Let your conscience be your guide." Is that good advice? It depends.

Before we answer, let's consider what a conscience is supposed to do. It should guide you in making decisions concerning right and wrong, and it should evaluate your past actions and render judgment on whether you did the right or wrong thing in a given circumstance. Your conscience serves as both a book of laws and as the courtroom to decide when and where those laws apply. St. Paul says that the conscience alternates between accusing and excusing; sometimes it declares your actions as wrong while other times it declares your actions right.

Everyone has a conscience. In Romans 2 St. Paul describes this as the law written on the hearts of all people. He uses the example of the Gentiles, or pagans, who have never heard the Ten Commandments or read the Bible, yet they by nature do what God's Law requires of them. All humans have an inborn sense that Someone created them and that they are accountable to that Someone for right or wrong behavior, even if they don't personally know who that Someone is. God's Law is written on their hearts, which is witnessed by the fact that they have consciences.

Now if God has written His Law on the hearts of all people, does that mean that all consciences are perfectly accurate? By no means. St. Paul says that the fall into sin darkened the conscience and hindered men from being able to always discern right from wrong. A former pastor of mine describes this darkening of conscience as "the Vaseline of sin." If you look at a clean mirror you can see yourself clearly; if you smear Vaseline over that clean mirror and look at yourself, the image will be blurred. Similarly, every human conscience is blurred because of sin so that it cannot always clearly discern right from wrong.

Because of sin, everyone is born with a faulty conscience. It judges correctly sometimes, but is not always trustworthy. Therefore, it is bad advice to tell someone whose conscience doesn't work properly, "Let your conscience be your guide." It would be like telling someone with a faulty compass, "Let your compass lead you."

So what's the solution? There are two, actually. First, sometimes unbelievers, even with their darkened consciences, can nonetheless espouse lofty moral theories and practice great virtue, as we see in the case of Aristotle's Ethics or in the noble behavior of certain ancient Greeks and Romans. So unbelievers can actually have their consciences guided by wise philosophers and educators who, even if they don't believe in the One True God, they still have a pretty good sense of right from wrong. This is what we call natural law. By observing the behavior of humans and the natural order of God's creation, and by studying history, we can gauge right behavior and wrong behavior.

To use a fairly crass example, we can learn from natural law that homosexual behavior is inherently unnatural and therefore wrong. If everyone were to only practice homosexuality, then our species would die out pretty quickly, which is a pretty big clue that it's unnatural. Likewise, homosexual behavior does all kinds of terrible harm to the body. Or to use a less crass example, natural law can teach us that drinking too much alcohol is wrong because it makes the head hurt the next day, causes poor decision-making, and prevents performing jobs or family obligations well. We can understand from the natural order of things that drunkenness is wrong, because God's judgment falls on it through various obvious punishments. So because of natural law, it is possible for even unbelievers to have fairly accurate consciences and even lead outwardly moral lives in so far as they order their lives according to natural law.

Now the other solution to the problem of faulty consciences is pretty obvious to the Christian; for the Christian, conscience is informed about the difference between right and wrong by the Law of God. Through Moses at Mount Sinai, God gave men His Law written on two Tables of stone. The Moral Law, expressed in the Ten Commandments, is intended to be the guide for everyone's conscience to follow. We study the whole Bible to properly interpret and apply what each of those commandments means. The Law of God enlightens our consciences to what is right and wrong. For the person who knows and believes God's Word thoroughly, it is good advice to say, "Let your conscience be your guide." However, we should remember that even Christians remain sinners and so our consciences are subject to error if we misinterpret or misapply the Word of God.

Jesus confirmed that the biblical Moral Law is valid for all time and binding upon all men in Matthew 22:37-40. He summarized God's Law this way: "You shall love the Lord your God with all your heart and with all your soul and with all your mind. This is the great and first commandment. And a second is like it: You shall love your neighbor as yourself. On these two commandments depend all the Law and the Prophets."

To illustrate our discussion of God's Law and conscience I want to talk a bit about how important conscience is to Lutherans. The Lutheran Reformation began in the conscience of Martin Luther. We just heard the greatest commandment from Jesus. Let's connect this commandment of Jesus to Luther's struggle of conscience. That commandment of Jesus, to love the Lord with your whole being and to love the neighbor as yourself, penetrated to the very depths of Martin Luther's conscience so that he was acutely aware of every time he failed to love the Lord his God with all his heart and with all his soul and with all his mind; every time he failed to love his neighbor as himself he was struck with guilt and the fear of eternal punishment.

Luther came to realize the enormous demands God's Law places upon the individual. God's Law deals not just with outward works, but also inward attitudes. Not only do we sin when we act against God's commandments, we also sin when our hearts desire to break one of the commandments. Not only do we sin when we fail to show love to others, we also sin when our hearts are enflamed with anger toward another. In view of these strict demands, Luther was crushed under the weight of his guilty conscience. He feared condemnation for his sins.

When Luther talked to others about his pangs of conscience, his friends would say: "Just try the best you can to avoid sin, work hard to follow the Law, and God will give you grace to help you do good works to make up the difference." That was their recipe for obtaining a clear conscience before the judgment seat of God. So Luther tried that method. And boy did Luther try! The "good works" prescribed were a never-ending routine of fasting, prayer, saying Masses, pilgrimages, and all manner of bodily deprivations. Yet these all failed to clear his guilty conscience. Though he had achieved a high degree of outward righteousness, he still found nothing but sinful thoughts in his heart. This led him to conclude that all his outward righteousness wasn't enough to "make up for" the inward unrighteousness of his heart. Also, his study of the Holy Scriptures had led him to conclude that many of the "good works" he had been doing were not commanded in God's Word, so how could he be certain that they were pleasing to God?

So the advice to Luther to try harder and work more only lead to greater sorrow, sheer despair. This was a deadly serious situation because despair is the total abandonment of hope in God. Luther had no hope for eternal life; he only faced eternal death, the just punishment for his sins, and no good works of his own could pull him out of this pit.

At this point, you may be scratching your head, thinking, "That Luther was too hard on himself! He needed to lighten up and get some help with his self-esteem." Or you may try to distance yourself from Luther's experience by saying, "Surely Luther was mistaken. God's demands in the Law and threats to punish sin aren't as severe as Luther made them out to be. He was just a radical with an overactive conscience." Or you may identify with Luther's plight, saying, "Yes! I've been there! I've experienced great shame and guilt before the throne of God and feared judgment for my sins! I've thought, ‘My sin is so great that surely I am lost!'"

The third option is the only Christian response to Luther's situation. He had an acute awareness of God as the Judge—the One who sees all our misdeeds, knows our darkest thoughts, and recognizes that every good work we do is tainted by self-interest. God the Judge is revealed in the Scriptures and is to be feared by all. Though Luther was publicly a very righteous man, he was right to sense such great guilt and shame before God. No advice to lighten up or seek a boost of self-esteem or try to lessen the demands of God's Law or diminish God's harsh judgment on sin could ease the guilt and fear he was experiencing.

The only thing that could rescue Luther's conscience was the Gospel, the Good News that God offers forgiveness of sins and eternal salvation freely for the sake of Jesus the Savior, who died for our sins and was raised for our justification. As Luther studied Romans and the Psalms he discovered this doctrine of justification: the Christian's righteousness before God is God's gift to the Christian for the sake of Jesus. No longer did Luther need to sooth his troubled conscience by providing God with proof of his own righteousness. His conscience was cleansed by the saving, forgiving blood of Christ, as our Epistle reading in Hebrews says: 13 For if the blood of goats and bulls, and the sprinkling of defiled persons with the ashes of a heifer, sanctify for the purification of the flesh, 14 how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God. 15 Therefore he is the mediator of a new covenant, so that those who are called may receive the promised eternal inheritance, since a death has occurred that redeems them from the transgressions committed under the first covenant.

In other words, if the Old Testament blood sacrifices could do outward purifications for the Jews, then certainly the blood of the Lord Jesus Christ can purge our consciences from guilt and works righteousness—the blood of Christ purifies our consciences by removing our guilt and declaring us righteous and forgiven. The blood of Jesus Christ, the New Testament in Jesus' blood, opened the gates of paradise for Martin Luther. This was the great event that started the Reformation. When Luther finally came to apply this truth of the Gospel to his own situation, he found salvation from eternal damnation on account of his sins and was rescued from an oppressively evil conscience that could find no relief in his own efforts and works.

We can learn a lot from Martin Luther's struggle of conscience. First, we must all follow in Luther's footsteps and have active consciences that judge sin and doctrine according to God's Word, the Holy Bible. We must humbly acknowledge the weakness of our faith and our constant need for God's help. Since we never become perfect saints this side of heaven, we need to have our consciences shaped and molded by the Word of God. Then we will be convinced of the radical depth of our sinfulness and seek to have our consciences cleansed by the liberating forgiveness of sins delivered in the preaching of the Gospel and given out in the sacraments. Only with consciences sharpened and made sensitive by God's demanding Law will we recognize our great need for Christ's death in our place and God's grace offered at this altar.

But if our consciences are flabby and inactive and are not formed by God's Word, then the Lutheran faith will never make sense. It is only the sick who need a doctor, right? Once Luther said that three things are necessary for everyone who desires to be saved. Like a sick person: 1. He must know what his sickness is. 2. He must know where the medicine is which will cure him. 3. He must desire and seek the medicine, and have it brought to him. The diagnosis and cure are both described in Luther's Small Catechism, which is what all of us Lutherans are taught in youth and adult confirmation, and it is the doctrine we all should cling to our whole lives through.

Our sickness is that we are dead in sin; this is revealed to us by the Ten Commandments, which we have not kept. The medicine is God's grace shown in Christ's death and resurrection and given out by the Holy Spirit in the Christian Church; this is made known to us in the Apostles' Creed. We seek and ask for God's grace in the Lord's Prayer, and His grace is delivered to us in the Sacraments: Baptism, Absolution, and the Lord's Supper.

Do you want to sharpen and strengthen you conscience? Then study your Small Catechism. It is "the roadmap into the Bible." It is the prayer book of the Lutheran church. Commit it to memory. Use it in daily devotions and prayers. It is not just for children, and studying the Catechism isn't child's play, but hard work. Yet the blessings are overflowing, and diligent use of the Catechism will aid your conscience now and in the hour of death.

When your conscience gets lazy and tries to excuse your sins rather than repent of them, then focus on the Ten Commandments, which reveal that "God threatens to punish all who break these commandments. Therefore, we should fear His wrath and not do anything against them." Use such warnings to keep your sinful flesh in check and to drive you to repentance.

When your conscience is consumed by guilt and the fear of condemnation, then focus on the Apostles' Creed, Baptism, Absolution, and the Lord's Supper, which all reveal God's grace and mercy toward you. In them you find the forgiveness of your sins—the removal of your guilt—and "where there is forgiveness of sins, there is also life and salvation."

Often first-time visitors to Lutheran worship services have trouble making sense of the flow of the liturgy. The Lutheran Divine Service makes sense only in light of the importance of the Christian having a clean conscience in the presence of God. Only with a conscience cleansed from sin can we enter into God's presence on Sunday to worship Him rightly. That is why at the beginning of the Divine Service we confess our sins and hear that they are forgiven.

Actually the whole service functions to reveal our sin before God, convict our consciences of guilt, bring us to repentance, and then offer cleansing of consciences through the forgiveness of sins offered in the Gospel and the Lord's Supper. That same cleansing will give you strength and encouragement for righteous living so that you may daily live according to your conscience and struggle against sin.

May God grant to us consciences taught by the Law of God and comforted by the precious Gospel of our Lord Jesus Christ, who was put to death for our sins and raised for our justification. Let us learn that a purged conscience is a good one, for it is one that is cleansed and forgiven by the blood of Jesus Christ, our Savior. In the name of the Father, and of the Son and of the Holy Spirit. Amen.

And the peace of God which passes all understanding will keep your hearts and minds in Christ Jesus unto life everlasting. Amen.