When is a Sin Mortal? (Father Simon Says)

A caller named Pat called into Father Simon Says with a question many Catholics quietly carry: What is a mortal sin, and what should I do with troubling thoughts that I do not want?

Father Simon began with reassurance. Not every bad thought is a mortal sin. In fact, unwanted thoughts are not the same as freely choosing sin. As he told Pat, “The minute you say, ‘I don’t want to think this way,’” that is not full consent of the will.

He also pushed back on the idea that confession is only for mortal sins. Regular confession of venial sins can be a beautiful grace. Naming those faults helps us stay honest, humble, and aware of our need for God’s mercy. At the same time, Father Simon gently warned against scrupulosity, that anxious habit of examining every thought too harshly and forgetting that the Lord is merciful.

Then he laid out the Church’s classic understanding of mortal sin. Three things are required: grave matter, knowledge, and full consent of the will. If one of those is missing, the sin is not mortal. That clarity can bring real peace to a troubled conscience.

For those battling sins of the imagination, Father Simon offered practical wisdom: turn immediately to the Hail Mary. He called it a powerful prayer that helps break the momentum of temptation and replace vice with virtue.

His advice was simple and deeply Catholic: trust God’s mercy, form your conscience well, and do not confuse every struggle with a break in your relationship with God.

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