What is the difference between mortal and venial sin?

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The Catechism of the Catholic Church defines sin as “the failure in genuine love for God and neighbor caused by an attachment to certain goods. Sin wounds the nature of man and injures human solidarity.”

Translation: sin is when you miss the mark – when you choose something of lesser importance over God, another person, or your true self.

It doesn’t take much reflection to understand that not all sin is the same. Intentionally taking someone else’s life and being short tempered with someone are not morally equivalent. The First Letter of St. John says that all wrongdoing is sin, but not all sin is deadly. That is a distinction that the Church still holds today in distinguishing between mortal and venial sin. 

Venial sin is present when you act against the moral law, even in small ways such as when you slack off at work, when you binge watch Netflix and still claim you are too busy to call and check in on loved ones. We all know this list could go on. 

Mortal sin is more serious. For a sin to be mortal, three conditions have to be met. First, it has to entail “grave matter,” which means that the act itself is serious (serious according to God’s criteria, not ours!). Secondly, you have to have full knowledge that what you are doing is grave matter. Third, you have to give complete consent to the act. 

Mortal sin is a deliberate decision, by which you are saying, “I know this is a bad thing to do, and I am going to freely choose in this moment to do it anyway.” Mortal sin requires a sacramental confession to be forgiven (and so you can receive the Eucharist). 

A quick case study: John knows Catholics cannot eat meat on Fridays during Lent. He thinks about this while at lunch and says, “I know what the Church says but who cares?” Then, he proceeds to eat a hamburger. All criteria seems to be met for mortal sin. On the other hand, Jane also knows the Church’s Lenten observances but honestly doesn’t think about it being Friday until after her hamburger. She did not give her complete consent to the act, so it is not a mortal sin. It was just a mistake.

Always remember, whether sin is mortal or venial, it is bad for us and is not good enough for our hearts and the plans of love God has for us. If you have mortal sin on your conscience, come to confession, the sacrament of mercy. Nothing is bigger or stronger than God’s mercy.  If you have no mortal sin, it is still important to ask forgiveness for our venial sins, even small ones. Make a regular practice of confession.

Think of it like a car wash. If you have gone mudding (mortal sin), get to the wash right away. If your vehicle gets dirty ever so often (venial sin), it is still good to get it washed every three or four months!

Father Rob Johnson is pastor of Mother of Perpetual Help in Maryville and chaplain of Southern Illinois University at Edwardsville.