Here are the List of Mortal Sins Every Catholic Should Know

The Two Types of Sin

All sin is an offense against God and a rejection of his perfect love and justice. Yet, Jesus explains the difference between two types of sins. We call the most serious and grave sins, mortal sins. Mortal sins destroy the grace of God in the heart of the sinner. By their very grave nature, a mortal sin cuts our relationship off from God and turns man away from his creator. St. Paul’s letter to the Hebrews tell us that “if we sin willfully after having the knowledge of the truth, there is now left no sacrifice for sins” (Hebrews 10:26). The second type of sin, venial sin, that of less grave matter, does not cut us off from Christ. Moreover, venial sin does weaken grace in the soul and destroys our relationship with God. A person who always takes part in venial sin is very likely to collapse into mortal sin if they continue in their evil ways.

So what kind of Sins are Mortal?

A mortal sin meets three conditions:

Mortal sin is a sin of grave matter
Mortal sin is committed with full knowledge of the sinner
Mortal sin is committed with deliberate consent of the sinner

This means that mortal sins cannot be done “accidentally.” A person who commits a mortal sin is one who knows that their sin is wrong but still deliberately commits the sin anyway. This means that mortal sins are “premeditated” by the sinner and thus are truly a rejection of God’s law and love.

The first condition, that a mortal sin is of grave matter, means that certain premeditated offenses against God are more severe than others. We know that some sins are graver than others (e.g. it is a graver sin to murder someone than to lie to someone). St. John explains, “If anyone sees his brother sinning if the sin is not deadly, he should pray to God and he will give him life. This is only for those whose sin is not deadly. There is such a thing as deadly sin, about which I do not say that you should pray. All wrongdoing is sin, but there is sin that is not deadly.” (1 John 5:16-17). Thus St. John differentiates between mortal and venial sin. Jesus also warns us that “Anyone who does not remain in me will be thrown out like a branch and wither; people will gather them and throw them into a fire and they will be burned” (John 15:6).

What kinds of offenses against God constitute “grave matter”?

In the Bible, St. Paul gives us a list of grave sins. He states that anyone who commits these sins shall not enter the kingdom of God. “Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God” (Galatians 5:19-20). Paul also tells the Corinthians, “know you no that the unjust shall not possess the kingdom of God? Do not err: neither fornicators, nor idolaters, nor adulterers, Nor the effeminate, nor liers with mankind, nor thieves, nor covetous, nor drunkards nor railers, nor extortioners shall possess the kingdom of God” (1 Corinthians 6:9-10). These sins constitute grave matter, and if they are committed willingly and with full consent, constitute mortal sin.

The Church also instructs us that the sins of anger, blasphemy, envy, hatred, malice, murder, neglect of Sunday obligation, sins against faith (incredulity against God or heresy), sins against hope (obstinate despair in the hope for salvation and/or presumption that oneself can live without God or be saved by one’s own power) and sins against love (indifference towards charity, ingratitude, and/or hatred of God) also constitute grave matter. This list of grave sins is based on Jesus Christ’s interpretation of the gravity of the Ten Commandments. Grave sins can be classed as sins against God, neighbor, and self, and can further be divided into carnal and spiritual sins (CCC 1853).

Four other sins are considered grave also. These sins not only offend God, but men as well. Thus these four sins are called “the sins that cry to heaven for vengeance” and are likewise mortal sins. These grave sins are:

The voluntary murder (Genesis 4:10)
The sin of impurity against nature –Sodomy and homosexual relations (Genesis 18:20)
Taking advantage of the poor (Exodus 2:23)
Defrauding the workingman of his wages (James 5:4)

Note from the author: For those of you who do not comprehend why these particular sins are of grave matter, I would recommend that you refer to the Summa Theologiae of St. Thomas Aquinas. He does an excellent job of explaining why these sins are of grave matter, and also explores the counter-arguments and objections that some people have regarding these grave sins.

Here is some listing and description of grave sins:

The First Commandment, “You shall Worship the Lord Your God and him only Shall You Serve”


Idolatry is the worship, veneration or belief in false gods. Because it is a direct rejection of God, it is a grave sin (1 Corinthians 6:9-10). Idolatry includes worship of images (This does not mean that we cannot venerate religious images. Veneration of images such as a crucifix is veneration of the person depicted and not the actual image in and of itself.)


Because atheistic humanism falsely seeks man and human glory and rejects God, atheism is a grave sin (CCC 2125). It is a sin against the virtue of religion. St. Paul tells us, “For the wrath of God is manifested from heaven against all unholiness and injustice of those men that detain the truth of God in injustice” (Romans 1:18).

The Second Commandment, “You shall not take the name of the Lord your God in vain”


This grave sin is the uttering of hatred, reproach, defiance or speaking ill of God. Blasphemy against the Church, the saints and sacred things is also a grave sin (CCC 2148). It fails to give love and respect to our Creator. St. James speaks against sinners who “blaspheme the good name that is invoked upon you” (James 2:7).

Perjury and False Oaths:

Those who take an oath in the name of the Lord and fail to keep it, or break the oath at a later date, show a grave lack of respect for the Lord of all speech (CCC 2152). Pledging oneself to commit an evil deed is also sinful. During his Sermon on the Mount, Jesus speaks against sinners who give false oaths (Matthew 5:33-34).

The Third Commandment, “Recall the sabbath day, to keep it holy”

Deliberate failure of the Sunday obligation:

The Christian Sunday (the Lord’s Day) celebrates the new life of the world born in Christ’s Resurrection. All humans have a duty, to praise God and give him thanks. Thus all Christians are bound to involve in the Mass and must partake of the Eucharist at least on holy days of rite. Deliberate failure to do this constitutes a grave sin (CCC 2181).

The Fifth Commandment, “You shall not kill”


Direct and intentional killing is gravely sinful (CCC 2268). It is a sin that cries to heaven for vengeance, much like the murder of Abel at the hands of Cain. Indirect homicide can also be of grave nature (such as refusing to help a person in danger). Moreover, the Church instructs that self-defense is permissible for the preservation of a one’s life. If the attacker is mortally wounded or killed, then the death of the attacker is not a sin. Those who use unnecessary aggression in self-defense can sin mortally if the attacker is killed or gravely injured.


Human life starts at conception in the mother’s womb. For God tells us, “Before I formed you in the womb I knew thee, and before you were born I consecrated you” (Jeremiah 1:5). Abortion is therefore murder. The oldest Christian book (besides parts of the Bible) is the Didache, a book composed by the twelve apostles or their disciples. The Didache declares the ancient teaching of the Catholic Church, “You shall not kill the embryo by abortion and shall not cause the newborn to perish” (Didache 2,2). All Catholics who procure a completed abortion or involve in execution of an abortion are automatically excommunicated from the Catholic Church (CCC 2272 and CIC Canon 1314).


Suicide is murder of the self. It is against the love of God, self, family, friends, and neighbors (CCC 2281). It is of especially grave nature if it is intended to set an example for others to follow. Voluntary cooperation in a suicide is also contrary to the moral law. Moreover, the responsibility of and gravity of suicide can be diminished in the cases of grave psychological disturbances, anguish, grave fear of hardship, suffering, or torture. But this does not make it morally permissible, and it is the judgment of God that will measure the gravity or responsibility of the sin.

Extreme Anger:

”Anger is a desire for revenge. If anger reaches the point of a deliberate desire to kill or seriously wound a neighbor, it is gravely against charity; it is a mortal sin (CCC 2302). Christ talks against anger saying, “Everyone who is angry with his brother shall be liable to judgment (Matthew 5:22).”
Hatred—Hatred of a neighbor is to deliberately wish him evil, and is thus a grave sin (CCC 2303 and Galatians 5:19-20).

The Sixth Commandment, “You shall not commit adultery”


Adultery is marital infidelity. A married person who has sexual relations with anyone but their lawful spouse, even transient sexual relations, commits adultery (CCC 2380).


The grave sin of divorce condemns those who divorce and remarry (Matthew 5:32) and those who divorce in the civil sense (except by grave dispensation). Hence divorce between two baptized Christians is a mortal sin (CCC 2384).


Pornography shows intimate real or simulated sexual acts to a third party. Because it removes the marriage act from within the sacramental sanctity of marriage and perverts sex, it is gravely contrary to charity (CCC 2354). The display of pornography to children and other parties is especially gravely sinful because it is gravely scandalous.


Prostitution brings a person down to an instrument of sexual pleasure and lust. It is gravely contrary to charity and chastity and defiles the body, the temple of the Holy Spirit. Moreover, destitution, blackmail or social pressure can reduce the gravity of the sin. Still, prostitution is always a sin (CCC 2355).


”Masturbation is the deliberate stimulation of the sexual organs in order to derive sexual pleasure” (CCC 2352). The Church instructs that sex has two main reason that must be sought in the marriage act: sex is for reproduction of children within a valid marriage, and it is a loving, unifying act between husband and wife. Masturbation violates both aspects of natural law and is thus a grave sin.

The Seventh Commandment—”You shall not steal”


All persons have a right to lawful private property obtained by legitimate work, inheritance or gift. To violate a person’s right to property by theft is a grave sin, particularly if the loss of the property will severely hurt the victim (CCC 2408). The gravity of theft is determined by the harm it does to the victim. A poor beggar who steals a loaf of bread commits a less grave sin than a rich man who steals the savings of a destitute person. St. Paul tells us that thieves shall not inherit the kingdom of God (1 Corinthians 6:9-10).


Lukewarmness is abstinence in response to God’s charity. It can also mean the refusal to give oneself to the prompting of charity (CCC 2094).

Hatred of God:

This grave sin is born of pride and is contrary to the love of God. A sinner who hates God willfully rejects him. Hatred of God refuses to affirm and praise God’s goodness and obedience (CCC 2094).

Please note that this is certainly not an absolute list of sins. The sins that are listed above are those of grave matter that can become mortal sins if they are done willfully and with full knowledge of their nature. Other sins are of venial nature and are less grave than the ones listed above.

What is venial sin?

As explained before, venial sin is a sin of lesser matter than grave sin. It can also be a sin of grave matter in which the sinner did not fully consent to the sin or did not have knowledge that his actions where sinful. Venial sins will not destroy grace in the soul, and will not directly cause a person who dies in the state of venial sin to lose the promise of heaven. Yet, venial sin weakens a person’s will to avoid evil and thus may indirectly lead to mortal sin. Anyways, all sin is an offense against God and should be abstained.

All sins can be forgiven

A person who repents of their sin intends to live a new life of grace and receives the Sacrament of Reconciliation for the forgiveness of all their sins (mortal sins, in particular, must be confessed in the Sacrament). Our sins can be forgiven because Jesus Christ paid for the price of human sin by dying on the cross for the redemption of humanity. Jesus Christ, true man, and true God was the perfect sacrifice for human sin and as a result delivered those who are baptized, repent and believe in him.

Because a baptized Christian can still sin, Christ instituted the Sacrament of Reconciliation for the forgiveness of our sins. Jesus gave the power to forgive sins in his name to the Church. He told his apostles, “Receive the Holy Spirit. Whose sins you forgive are forgiven them, and whose sins you retain are retained” (John 20:22–23). This means that the apostles and their successors, the priests and bishops of the Catholic Church, can forgive sins in Jesus’ name.

It is very crucial that Catholics confess sins often, particularly if we are in the state of mortal sin. A person who dies in mortal sin cannot enter the kingdom of heaven and is doomed to eternal suffering in hell. Even when we have not committed a mortal sin, we are still obliged to confess our sins at least once a year. Christ, in perfect love, laid down his life so that we may be forgiven of our sins. The sacrifice of the cross should not be ignored or taken for granted. Jesus died for the life of the world and is thus the light of the world. “He that followeth me, walketh not in darkness, but shall have the light of life” (John 8:12)




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