Does “Grave Sin” mean “Mortal Sin”?

By Deacon Frederick Bartels

A careful reading of Church documents like canon law or the Catechism (and others), reveals that when the Church uses the term “grave sin” it means “mortal sin.” Here are a few examples:

Can. 916: “A person who is conscious of grave sin is not to … receive the body of the Lord without previous sacramental confession …”

The content of Canon 916 implies that “grave sin” is used to mean objectively “mortal sin,” as evidenced by the prohibition against those conscious of grave sin from receiving the Eucharist.

The same goes for the following:

CCC 2181: “The Sunday Eucharist is the foundation and confirmation of all Christian practice. For this reason the faithful are obliged to participate in the Eucharist on days of obligation, unless excused for a serious reason (for example, illness, the care of infants) or dispensed by their own pastor. Those who deliberately fail in this obligation commit a grave sin.” (emphasis added)

CCC 1385: “Anyone conscious of a grave sin must receive the sacrament of Reconciliation before coming to communion.”

The Church is clearly teaching that missing Mass on a day of obligation without a serious reason for doing so is a grave (objectively mortal) sin which requires sacramental confession.

Further evidence that grave sin means mortal sin:  Pope John Paul II’s statement from a 1984 post-synodal apostolic exhortation:

“Considering sin from the point of view of its matter, the ideas of death, of radical rupture with God, the supreme good, of deviation from the path that leads to God or interruption of the journey toward him (which are all ways of defining mortal sin) are linked with the idea of the gravity of sin’s objective content. Hence, in the church’s doctrine and pastoral action, grave sin is in practice identified with mortal sin.” (emphasis mine)

Finally, we should not confuse “grave matter” with “grave sin” or “mortal sin.” Grave matter refers to the gravity or seriousness of the offense. Therefore the Church teaches that mortal sin requires grave matter (as normally specified by the 10 commandments), full knowledge, and complete consent. Those three criteria must together be met to constitute the guilt of mortal sin.

For example, if a Catholic misses Mass without a serious reason for doing so it involves grave matter. Provided that the person knows it is seriously wrong, and freely chooses to do so anyway, he has committed mortal sin. In the language typically used by the Church, he has committed grave sin and thus must ordinarily receive the sacrament of Penance prior to receiving the Eucharist because he has severed his relationship with God and is no longer properly disposed to receive the body and blood of Christ.

As another example, suppose a Catholic did not know that missing Mass without a serious reason was gravely wrong. In that case, he would lack full knowledge and thus would not be guilty of mortal sin, but perhaps only a venial sin.

In summary, when the Church uses the phrase “grave sin” we can take it to mean objective “mortal sin.” The word “objective” is used here in reference to the fact that no one but God alone can judge the subjective state of a person’s soul.