Reader's question:

Good day,
I’m writing to you because I would like to know exactly what is meant by mortal sins.
Kind regards

Answer:

Dear reader,

by mortal sin we mean that sin which causes the loss of God’s grace, thereby breaking friendship with Him. Mortal sins are also called grave sins, because they always involve serious matter. For a sin to be considered mortal, three conditions must be present: grave matter, full knowledge of the mind, and deliberate consent of the will. If even one of these conditions is missing, we cannot speak of mortal sin.

Here is how the Catechism of the Catholic Church describes mortal sin:

“Mortal sin destroys charity in the heart of man by a grave violation of God's law; it turns man away from God, who is his ultimate end and his beatitude, by preferring an inferior good to him.” (CCC 1855)

“Mortal sin, by attacking the vital principle within us - that is, charity - necessitates a new initiative of God's mercy and a conversion of heart which is normally accomplished within the setting of the sacrament of reconciliation:

When the will sets itself upon something that is of its nature incompatible with the charity that orients man toward his ultimate end, then the sin is mortal by its very object . . . whether it contradicts the love of God, such as blasphemy or perjury, or the love of neighbor, such as homicide or adultery.... But when the sinner's will is set upon something that of its nature involves a disorder, but is not opposed to the love of God and neighbor, such as thoughtless chatter or immoderate laughter and the like, such sins are venial.¹” (CCC 1856)

So alongside mortal sin there also exists what is called venial sin. This type of sin does not result in the loss of sanctifying grace, since it “allows charity to subsist, even though it offends and wounds it.” (CCC 1855)

Many people think that mortal sin only means killing, but as the Catechism shows, there are many other sins that involve grave matter and are therefore mortal sins. Chief among these are sins against God, such as hatred of God, blasphemy, or heresy, and sins against the sixth commandment—that is, sins against purity. These are always grave sins, such as masturbation, fornication, and adultery. Some sins, however, may be either mortal or venial, such as theft. There is a difference between stealing a large sum and taking something trivial that harms no one.

This is certainly not an exhaustive list, since there are other mortal sins that can be committed. We must do everything we can to avoid sin, both mortal and venial, because every sin is an offense against God, who loves us infinitely and deserves to be loved in return. Sometimes, unfortunately, we fall—but we have the wonderful opportunity to turn to the infinite mercy of God through the sacrament of Reconciliation, and thus recover the grace we have lost.

God bless you!

Giuseppe                              

¹St. Thomas Aquinas, STh I-II, 88, 2, corp. art.