Mortal Sin and Venial Sin

Catechism

Catechism 1854–1864

Mortal sin destroys charity in the heart and cuts a person off from God; venial sin wounds the relationship without severing it. Three conditions must all be met for a sin to be mortal.

What the Church Teaches

The Church distinguishes two kinds of sin, and the distinction is not about how bad it looks from outside. Mortal sin destroys charity in the heart by a grave violation of God’s law; it turns a person away from God. Venial sin offends and wounds charity without destroying it (CCC 1855).

The three conditions for mortal sin

  1. Grave matter. The act itself must be seriously wrong — the Catechism points to the Ten Commandments as the measure (CCC 1858).
  2. Full knowledge. The person must know that it is gravely wrong.
  3. Deliberate consent. The choice must be free and personal — enough consent to make it genuinely one’s own.

All three are required (CCC 1857). If any is missing, the sin is not mortal — which is why ignorance, compulsion, fear, habit, and psychological factors can reduce or even remove culpability (CCC 1860).

Where This Comes From

St. John distinguishes sin that is deadly from sin that is not (1 John 5:16–17) — the Church’s terminology comes directly from that verse. Christ’s own teaching assumes degrees: some things defile a man, some servants are beaten with many stripes and some with few, and the widow’s mite is weighed differently from the rich man’s gift.

Common Misunderstandings

  • "Venial sin doesn’t matter." It matters. Deliberate and unrepented venial sin disposes us little by little to commit mortal sin (CCC 1863). The Catechism’s image is of something that weakens the will gradually rather than breaks it at once.
  • "I’ve committed a mortal sin, so I’m damned." No. Mortal sin is forgiven in Confession, and it is forgiven completely. The Church has never taught that anyone is beyond mercy while they live.
  • "I can tell whether someone else is in mortal sin." You cannot, and neither can I. Two of the three conditions are interior. The Catechism is explicit that judgment of persons is entrusted to God alone (CCC 1861).
  • "If I’m not sure, I should stay away from Communion." If you are genuinely unsure whether a sin was mortal, ask a priest — the confessional is exactly where that question gets answered.

What It Means in Practice

Confess grave sin before receiving Communion, and do not let uncertainty become a reason to drift away from the sacraments for years. Regular Confession, even when nothing grave has happened, is how most people keep the small things small.

Pray With This

In the Catechism

  • 1854–1864 — the gravity of sin: mortal and venial
  • 1857–1859 — the three conditions
  • 1846–1848 — mercy and sin, which the Catechism puts first, deliberately

Read the full text at vatican.va.