“For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, but a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries. He that despised Moses’ law died without mercy under two or three witnesses: of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace? For we know him that hath said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge his people. It is a fearful thing to fall into the hands of the living God.” Hebrews 10:26-31

Very few preachers speak of mortal and venial sin any more. Instead, they treat all sin as though it’s really not a big deal. Yet the Bible, as well as the Lutheran Confessions, clearly speaks of both mortal and venial sins.

For example, John writes in his first epistle: “If any man see his brother sin a sin which is not unto death, he shall ask, and he shall give him life for them that sin not unto death. There is a sin unto death: I do not say that he shall pray for it. All unrighteousness is sin: and there is a sin not unto death” (5:16-17).

In the Apology to the Augsburg Confession, Melanchthon writes: “But since we speak of such faith as is not an idle thought, but of that which liberates from death and produces a new life in hearts, [which is such a new light, life, and force in the heart as to renew our heart, mind, and spirit, makes new men of us and new creatures,] and is the work of the Holy Ghost; this does not coexist with mortal sin [for how can light and darkness coexist?], but as long as it is present, produces good fruits, as we will say after a while” (Art. IV, Par. 64f.).

In the Smalcald Articles, Luther writes: “It is, accordingly, necessary to know and to teach that when holy men, still having and feeling original sin, also daily repenting of and striving with it, happen to fall into manifest sins, as David into adultery, murder, and blasphemy, that then faith and the Holy Ghost have departed from them [they cast out faith and the Holy Ghost]. For the Holy Ghost does not permit sin to have dominion, to gain the upper hand so as to be accomplished, but represses and restrains it so that it must not do what it wishes. But if it does what it wishes, the Holy Ghost and faith are [certainly] not present. For St. John says, 1 John 3:9: Whosoever is born of God doth not commit sin, … and he cannot sin…” (Art. III, Par. 43ff.).

So, what are mortal and venial sins? Both are transgressions of the law, and both are deserving of God’s eternal wrath and punishment (cf. 1 John 3:4; Rom. 6:23a; Ezek. 18:4).

Venial sins are those sins a Christian commits unintentionally or in moments of weakness but then repents and seeks God’s forgiveness for the sake of Christ Jesus and His atoning sacrifice upon the cross. Old Testament sacrifices could be offered for venial, unintentional sins but not for willful and intentional sins.

And, indeed, all Christians commit venial sins. The Bible tells us: “If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he is faithful and just to forgive us our sins, and to cleanse us from all unrighteousness … My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous: and he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world” (1 John 1:8-9; 2:1-2).

Mortal sins are those sins that people commit willfully and intentionally and which drive out the Holy Spirit and destroy faith in Christ. They are called mortal sins because, unless one is graciously brought to repentance and faith in Christ, they lead to eternal death and damnation.

Unbelievers continue in mortal sins, but believers too can fall into mortal sin if they reject the regenerating work of the Holy Spirit and intentionally turn back into sin and disobedience.

It is why David prayed: “Cast me not away from thy presence; and take not thy Holy Spirit from me” (Ps. 51:11); and why Paul warned the believers at Ephesus: “And grieve not the Holy Spirit of God, whereby ye are sealed unto the day of redemption” (Eph. 4:30). It is also why Paul warns against abusing our liberty in Christ to sin in Romans 6.

If we willfully reject the Word of God and turn back into sin, we drive out the Holy Spirit and turn away from Christ who redeemed us. And when we reject the work of the Holy Spirit and turn away from Christ to go our own way, what hope is there for us?

That is why the writer to the Hebrews cautions us: “If we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins, but a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries. He that despised Moses’ law died without mercy under two or three witnesses: of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace? For we know him that hath said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge his people. It is a fearful thing to fall into the hands of the living God” (Heb. 10:26-31; cf. 6:4ff; 2 Pet. 2:18ff.).

John also writes: “Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law. And ye know that he was manifested to take away our sins; and in him is no sin. Whosoever abideth in him sinneth not: whosoever sinneth hath not seen him, neither known him” (1 John 3:4-6).

What’s my point in speaking to you of mortal and venial sin?

First of all, we all sin daily in our thoughts, desires, words and actions; and we all are in constant need of God’s mercy and forgiveness in Christ Jesus! It is why we examine ourselves, confess our sins and continually seek God’s mercy and forgiveness through confession and absolution. It’s why we return daily to the blessings offered and given to us through the preaching of the Gospel and in our Baptisms. It’s why we partake often of the very body and blood of Christ which was sacrificed for us on the cross and is given to us in the Lord’s Supper for the remission of our sins.

And, secondly, lest we deceive ourselves into thinking we can be Christians and continue on wilfully in disobedience to God’s commandments — whether that be misusing God’s name, neglecting His Word and Sacraments, disobeying parents and other authorities, causing harm to others, viewing pornography or participating in an illicit sexual relationship, being dishonest in our dealings with others, participating in slander or gossip, or coveting persons or property — we should take to heart God’s warnings concerning mortal sin and know that we cannot willfully continue in sin and still have faith in Christ. The two just don’t go together! Rather, God would have us repent of our sinful ways, looks to Christ in faith for mercy and then seek God’s help and strength to amend our sinful ways and live for Christ, in accord with God’s commandments.

Therefore, I ask you to examine yourselves and confess your sins before the LORD God, seeking His mercy and forgiveness for the sake of Christ and His atoning sacrifice on the cross. If you are struggling with temptation and sin, confess your sins before God, look to Christ in faith for forgiveness and seek God’s help to amend your ways and to walk in accord with God’s commandments.

Remember that “we have an advocate with the Father, Jesus Christ the righteous: and he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world” (1 John 2:1,2).

And, if you are sorry for your sins and look in faith to Christ and His cross for forgiveness, I, as your minister, announce the grace of God unto you and, in the stead and by the command of our Lord Jesus Christ, forgive you all our sins in the name of the Father, and of the Son, and of the Holy Spirit. Amen.

[Scripture quotations are from the King James Version of the Bible.]