Many people don’t understand what the Church means by saying “mortal” and “venial” sin. What’s the big difference? All sins are wrong, right? While all sin is wrongdoing, there are some sins that are more serious than others. We should all be able to agree upon that point. After all, many people would say that killing someone is more serious than stealing, or that swearing at your parents is worse than disrespecting a stranger. Even the law differentiates between murder which is not thought out and murder which is pre-meditated.

What is Venial Sin?

Venial sins are the less serious of the two types of sin because they do not concern a grave matter or are committed in ignorance of the fact that the act is sinful. This will make more sense in the light of what constitutes mortal sin.

What is Mortal Sin?

Mortal sin is the more serious type of sin. In order for a sin to be considered mortal, it must meet three “conditions” (for lack of a better word):

  1. The object of the action was grave matter.
  2. The act was committed with full knowledge that it was sinful.
  3. The act was committed with the deliberate consent of the person.

(Catechism of the Catholic Church, paragraph 1857)

Let’s take each of those points one by one and explain what they mean in full.

1.   The object of the action was grave matter.

Grave matter is defined by the Church to be anything against the Ten Commandments (Catechism of the Catholic Church, paragraph 1858). However, some sins are more serious than others even within this category. As I have already stated, murder is a more serious offense than theft, and injuring one’s parents is more serious than injuring a stranger.

2.   The act was committed with full knowledge that it was sinful.

Mortal sins are committed with the person having full knowledge that the action was wrong. If this condition is removed (indeed, if any of the three conditions are removed from the situation) then the sin is not mortal. If a person is ignorant of the fact that the action is sinful, then it is a much less serious offense and is a venial sin.

3.   The act was committed with the deliberate consent of the person.

This connects to the second condition. If a person knows the action to be sinful and then deliberately commits the sin anyway, the offense is greater than if the person had unknowingly and unwillingly committed the sin.

Mortal sins, because of their seriousness, “necessitate a new initiative of God’s mercy and a conversion of heart which is normally accomplished within the sacrament of reconciliation” (Catechism of the Catholic Church, paragraph 1856). For a biblical defense of the Sacrament of Reconciliation, see my post titled “Is Confession to a Priest Biblical?”.

But Wait a Minute! The Idea of Two Categories of Sin is Unbiblical.

Actually, this concept is found in Scripture. 1 John 5:16-17 states:

“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.”


The Catholic Church teaches that there are two types of sin: mortal sin and venial sin. Mortal sins are the more serious of the two and kill the life of God’s grace within the soul, while venial sins are less serious offenses that nonetheless wound charity.

Got Questions? Just Ask! Do you have a question about the Catholic Church or what you have read in this post? Comment and tell me about it! I’ll address your question in a post for everyone. If you have a more personal question, please feel free to email me. God bless and thanks for reading!

About catholicandlovinit

As the title of my blog suggests, I am Catholic and lovin' it! My interest is apologetics, or the defense of the Faith, which is the purpose that I intend for this blog to serve. Every now and then, I will post answers to common questions about the Catholic Faith to explain certain practices and customs. If you read my posts and have a question, shoot me a comment! I'm always happy to answer questions or to clarify something that was misunderstood. God bless and thanks for reading!

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