What is the difference between mortal and venial sin?

The Catechism reminds us, “Sin is an offense against reason, truth, and right conscience; it is failure in genuine love for God and neighbor caused by a perverse attachment to certain goods.  It wounds the nature of man and injures human solidarity.  It has been defined [by St. Augustine] as ‘an utterance, a deed, or a desire contrary to the eternal law'” (#1849).

Traditionally, Catholic moral theology has distinguished between a mortal and a venial sin.  In the First Letter of St. John, we read, “…All wrongdoing is sin, but not all sin is deadly” (5:17).  The notion of a “deadly” or mortal sin is found in other parts of Sacred Scripture as well:  For instance, St. Paul in Galatians (5:19-21) asserted, “It is obvious what proceeds from the flesh:  lewd conduct, impurity, licentiousness, idolatry, sorcery, hostilities, bickering, jealousy, outbursts of rage, selfish rivalries, dissensions, factions, envy, drunkenness, orgies, and the like.  I warn you, as I have warned you before:  those who do such things will not inherit the kingdom of God!”  (Confer also Romans 1:28-32, I Corinthians 6:9-10, and Ephesians 4:3-8).  Therefore, Sacred Scripture explicitly identifies certain sins which kill the grace of God in our soul and deprive a person of eternal salvation.

The Catechism presents the three criteria that must be satisfied for a sin to be mortal:  First, the act committed must be considered grave or serious matter.  Mortal sins are heinous in the eyes of God.  Throughout the moral section of the Catechism, sins are noted as “gravely sinful”:  for example, “The fifth commandment forbids direct and intentional killing as gravely sinful” (#2268).  Second, the sinner must have full knowledge of the sinful character of the act; in other words, he must be acting with an informed intellect and must know this act violates God’s eternal law.  Third, the sinner must give full consent of the will, meaning that he has reflected on doing the action and deliberately wants to do it.

Mortal sin destroys our union with God and the presence of sanctifying grace in our souls.  Because these are heinous actions in the eyes of God, for a person to knowingly and willingly commit them indicates a turning away from the love of God.  Anyone conscious of a mortal sin must undergo an interior conversion and then receive forgiveness and absolution through the Sacrament of Penance.  Until making a good confession and receiving sacramental absolution, anyone conscious of being in a state of mortal sin cannot receive Holy Communion, except under extraordinary circumstances, e.g. no possibility of going to confession (cf. Catechism, #1457).  Moreover, an unrepentant person guilty of mortal sin objectively risks eternal damnation in hell; however, “although we can judge that an act is in itself a grave offense, we must entrust judgment of a person to the justice and mercy of God” (Catechism, #1861).

On the other hand, venial sin denotes either an act of a less serious matter, or one which involves grave matter but is performed without full knowledge or complete consent of the will.  Unlike mortal sin which involves a complete turning away from God’s love, venial sin wounds our relationship with God.  The periodic confession of venial sins is also highly recommended as part of a good spiritual regimen.  Actually, all sin is serious since it hurts our relationship with our Lord.  Moreover, even venial sin can lead to mortal sin or become habitual if not corrected.  A practice of regular confession helps the individual better form the conscience, recognize faults and weaknesses, resist temptations, and receive God’s grace to heal and strengthen the soul.  St. Teresa of Avila said, “Always fear when some fault you commit does not grieve you.  For in regard to sin, even venial, you know that the soul must feel great sorrow….  For the love of God, take care never to grow careless about venial sin, however small….  There is nothing small if it goes against so great a sovereign.”

With this in mind, we can also approach the subject of fundamental option, an easily misunderstood topic today.  The idea of fundamental option is that each person makes a basic choice to love God, to accept His truth, and to be His disciple.  That choice though is lived-out each day of our lives by the individual choices we make to do good.  In this sense, fundamental option makes sense.

Sadly, some individuals misconstrue fundamental option in such a way there are no particular mortal sins.  Instead, the one “mortal sin” which would take a soul to hell is for a person to willingly, knowingly reject God and His love entirely.  Such a stance would reduce fundamental option to some psychological game, whereby a person says, “I love God.  I do not reject God.  My individual choices or particular actions do not affect my total being.  Therefore, although I committed adultery, or murdered someone, or fornicated, or robbed the bank, [or committed any other mortal sin], God still loves me, I love God, and I am going to heaven.”  Think again!  While only God can probe the depths of our soul and judge a person, those actions are objectively mortal sins.  To choose mortal sin indicates a contempt for the divine law.  To commit such actions evidences a lack of love for God and for neighbor.  In essence, particular mortal sins show a rejection of God.  Our Holy Father, John Paul II, wrote, “It thus needs to be stated that the so-called fundamental option… is always brought into play through conscious and free decisions.  Precisely for this reason, it is revoked when man engages his freedom in conscious decisions to the contrary, with regard to morally grave matter.  To separate the fundamental option from concrete kinds of behavior means to contradict the substantial integrity or personal unity of the moral agent in his body and in his soul” (The Splendor of Truth, #67).  Therefore, mortal sin can radically change the person’s fundamental option.  (Cf. Reconciliatio et Paenitentia, #17).

As we continue our spiritual journey in this life, we must not only renew each day the “fundamental” choice we have made for our Lord, but also repent of any sin and turn to our Lord for forgiveness.  Let us also pray for those– especially those in our family– who have gone astray and are not living a life with our Lord, that they will turn to the Lord, seek forgiveness, and come to a new life in Him.