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What is a mortal sin?


Hieronymus Bosch | Public Domain

Philip Kosloski - published on 07/22/19

The concept of a mortal sin is a biblical one, as well as something that appeals to natural reason.

Sin is not an easy topic to discuss, as we don’t like to admit our many faults and failings. However, if we do not examine ourselves and probe deeper into our sins and sin itself, we may not ever find true happiness in this life or the life to come.

Among the many facets in the topic of sin is the recognition of mortal sins. This is a classification that encompasses sins that sever our relationship with God.

The Catechism of the Catholic Church defines mortal sin as “a grave violation of God’slaw;” adding that such a sin “turns man away from God, who is his ultimate end and his beatitude, by preferring an inferior good to him“(CCC 1855).

Furthermore, “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” (CCC 1856).

This concept of types of sin that are more grave than others is a biblical one and can be found in the First Letter to John.

There is sin which is mortal …. All wrongdoing is sin, but there is sin which is not mortal. (1 John 5:16-17)

We might consider that Jesus also pointed his listeners to distinctions in “levels” of sin. He spoke about the sins of the heart that “defile” as something distinct from the various rules the Pharisees enjoined on their followers.

But what comes out of the mouth proceeds from the heart, and this defiles a man. For out of the heart come evil thoughts, murder, adultery, fornication, theft, false witness, slander. These are what defile a man; but to eat with unwashed hands does not defile a man. (Matthew 15:18-20)

Before any further discussion of sin, however, we should take a moment to speak of God’s readiness to forgive. Pope Francis likes to say that God never gets tired of forgiving.

The problem is that we ourselves tire, we do not want to ask, we grow weary of asking for forgiveness. He never tires of forgiving, but at times we get tired of asking for forgiveness. Let us never tire, let us never tire! He is the loving Father who always pardons, who has that heart of mercy for us all. And let us too learn to be merciful to everyone. Let us invoke the intercession of Our Lady who held in her arms the Mercy of God made man.

Now, to understand mortal sin further, we must also consider that in addition to the objective component to mortal sin (the sin itself), there is also a subjective element that must be taken into consideration (factors in the person committing the sin).

In order for a sin to be mortal, to sever our relationship with God, it must meet three specific qualifications as laid out by the Catechism.

Mortal sin requires full knowledge and complete consent. It presupposes knowledge of the sinful character of the act, of its opposition to God’s law. It also implies a consent sufficiently deliberate to be a personal choice. Feigned ignorance and hardness of heart do not diminish, but rather increase, the voluntary character of a sin. (CCC 1859)

To summarize the three qualifications, a mortal sin must be grave matter, committed with full knowledge and the person must have complete consent.

Read more:
What makes a sin “grave”?

This means that “unintentional ignorance can diminish or even remove the imputability of a grave offense” (CCC 1860). Also, when a person is forced to commit a grave offense, the sin is no longer mortal in nature.

Common sense of sin

The concept of a mortal sin is one that is in accord with natural reason , since we seem to know within our hearts there exists certain offenses that are greater than others. Stealing a candy bar from a store is bad, but stealing bread from a homeless person is something even worse.

If we find that we have committed mortal sin, the important part is to go to confession. In this sacrament, our sins, even if they are mortal, can be wiped clean by the mercy of God, who is already ready to receive us back into his fold and restore our relationship with him.


Read more:
How to go to confession, a step-by-step guide

Read more:
Can a non-Catholic go to confession to a priest?

SacramentsSpiritual Life
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