Mortal sins (
peccata mortalia) in
Catholic theology are wrongful acts that condemn a person to
Hell after death if unforgiven. These
sins are considered "mortal" because they constitute a rupture in a person's link to
God's saving
grace: the person's
soul becomes "dead", not merely weakened. A mortal sin is not necessarily a sin that cannot be repented, unlike an
eternal sin. Thus, even after a mortal sin has been committed, there is a chance for repentance. According to Catholic teaching, repentance and a firm resolution to sin no more (with at least
imperfect contrition) restores the link to God's saving grace in the
sacrament of penance; and restoration outside confession if the
contrition is perfect.
Perfect contrition arises from a love of God, who has been grievously offended by a sinful act. When perfect contrition is the means by which one seeks to restore one's relationship with God, there must also be a resolution to confess mortal sins in confession (if possible), as soon as possible. The verse from which the term "mortal" sin is derived likely comes from the
1 John 5:16-17.