The requirement to attend Mass on Sunday and other holy days of obligation, rooted in the Third Commandment and codified in Church law (cf. Code of Canon Law, canons 1246-48) is a serious obligation for all Catholics. A Catholic who (a) is able to attend Sunday Mass (i.e., who is not impeded by illness, lack of transportation, etc.), (b) knows the seriousness of this requirement, and (c) nonetheless freely chooses to miss Mass, thereby commits a mortal sin (cf. Catechism, no. 2181).
Before discussing the specific issue of missing Mass on Sunday, it is important to briefly review what constitutes a mortal sin. In general, sin is a failure to love God and neighbor caused by a perverse attachment to certain goods. Sin turns us away from God’s love for us and wounds our human nature. Like the sin of Adam, sin is rooted in disobedience. It is a revolt against God, and thus is diametrically opposed to the obedience of Christ, which achieves our salvation (cf. Phil. 2:6-9; Catechism, nos. 1849-50).
Church Teaching on Mortal Sin
The Catechism clearly reflects the traditional teaching of the Church that sins may be evaluated according to their gravity (no. 1854; cf. 1 Jn. 5:16-17). More serious sins are called mortal, less serious sins are called venial.
With the whole tradition of the Church, we call mortal sin the act by which man freely and consciously rejects God, His law, the covenant of love that God offers, preferring to turn in on himself or to some created and finite reality, something contrary to the divine will (conversio ad creaturam). This can occur in a direct and formal way in the sins of idolatry, apostasy, and atheism; or in an equivalent way as in every act of disobedience to God’s commandments in a grave matter (Pope John Paul II, Apostolic Exhortation Reconciliatio et Paenitentia , no. 17; cf. Catechism, no. 1855).
Mortal sin destroys the divine life (i.e., sanctifying grace) in the soul. One who commits a mortal sin needs “a new initiative of God’s mercy and a conversion of heart which is normally accomplished within the setting of the sacrament of reconciliation” (Catechism, no. 1856). In the absence of repentance and God’s mercy, mortal sin leads to the eternal death of hell (cf. Catechism, no. 1861).
The question then becomes, “What constitutes a mortal sin?” For a sin to be mortal, three conditions must be present:
(1) grave matter
(2) full knowledge of the evil of the act
(3) full consent of the will (cf. Catechism, no. 1857)
By “grave matter,” we are identifying types of behavior specified by the Ten Commandments that by their nature could lead us to forfeit our heavenly inheritance. St. Paul provides a partial list of such behaviors, which he calls “works of the flesh”: “Now the works of the flesh are plain: immorality, impurity, licentiousness, idolatry, sorcery, enmity, strife, jealousy, anger, selfishness, dissension, party spirit, envy, drunkenness, carousing, and the like. I warn you, as I warned you before, that those who do such things shall not inherit the kingdom of God” (Gal. 5:19-21; cf. Catechism, no. 1858).
Vatican II, in discussing crimes against the human person, likewise provides a list of acts that would constitute “grave matter”:
Whatever is hostile to life itself, such as any kind of homicide, genocide, abortion, euthanasia and voluntary suicide; whatever violates the integrity of the human person, such as mutilation, physical and mental torture and attempts to coerce the spirit; whatever is offensive to human dignity, such as subhuman living conditions, arbitrary imprisonment, deportation, slavery, prostitution and trafficking in women and children; degrading conditions of work which treat laborers as mere instruments of profit, and not as free responsible persons: all these and the like are a disgrace, and so long as they infect human civilization they contaminate those who inflict them more than those who suffer injustice, and they are a negation of the honor due to the Creator (Gaudium et Spes, no. 27).
At this point we must make a very important distinction. When we say that “missing Mass is a mortal sin,” we are speaking imprecisely. What we are actually saying is that missing Mass is seriously wrong—that is, “grave matter.” As the Catechism affirms, “we can judge that an act in itself is a grave offense,” but “we must entrust judgment of persons [i.e., whether a specific act is a mortal sin] to the justice and mercy of God” (no. 1861).
Why is this so? First, Our Lord instructs us not to judge others and to be more concerned about the plank in our own eyes (cf. Mt. 7:1-5). Second, as we saw above, there must not only be grave matter, but also full knowledge and consent, something an observer is typically in no position to evaluate. In this context, “full knowledge” refers to “knowledge of the sinful character of the act, of its opposition to God’s law” (Catechism, no. 1859).
Third, grave matter refers to particular choices of conduct. In moral theology, such a choice is called the object of the action. However, a full evaluation of the morality of an action also requires an examination of the circumstances and the intention of the acting person (cf. Catechism, nos. 1750-54).
All of this means, of course, that while we do not judge persons, we can assuredly judge—in accordance with God’s law as taught by the Church—that certain actions are gravely sinful: the “stuff” that mortal sins are made of.
It is especially important to affirm this truth today, as recent decades have seen the development of erroneous theories of morality which would tell us that we cannot classify certain types of behaviors as being always and everywhere gravely sinful. To respond to this contemporary challenge, Pope John Paul II issued his 1993 encyclical on Christian morality, called Veritatis Splendor (“Splendor of the Truth” [“VS”]).
Veritatis Splendor recognizes the importance of circumstances and intentions in evaluating the morality of human actions, but also affirms the Church’s perennial teaching that “there exist acts which per se and in themselves, independently of circumstances, are always seriously wrong by reason of their object” (VS 80, quoting Reconciliatio et Paenitentia, no. 17). In a footnote, the Pope quotes a 1967 address by Pope Paul VI on the same subject:
Far be it from Christians to be led to embrace another opinion, as if [Vatican II] taught that nowadays some things are permitted which the Church had previously declared intrinsically evil. Who does not see in this the rise of a depraved moral relativism, one that clearly endangers the Church’s entire doctrinal heritage? (VS, fn. 131).
Accordingly, Pope John Paul II says we must reject the thesis that:
it is impossible to qualify as morally evil according to its species—its “object”—the deliberate choice of certain kinds of behavior or specific acts, apart from a consideration of the intention for which the choice is made or the totality of the foreseeable consequences of that act for all persons concerned (VS 79, original emphasis).
It is never permitted to do evil that good may come from it (cf. Rom. 3:8). On this point, St. Paul was emphatic:
Do you not know that the unrighteous will not inherit the kingdom of God? Do not be deceived; neither the immoral, nor idolaters, nor adulterers, nor homosexuals, nor thieves, nor the greedy, nor drunkards, nor revilers, nor robbers will inherit the kingdom of God (1 Cor. 6:9-10).
In acts that are intrinsically evil—in other words, “grave matter”—a good intention or particular circumstances can diminish the person’s culpability, but the act itself remains disordered and “irremediably” evil. Thus the Holy Father teaches that “circumstances or intentions can never transform an act intrinsically evil by virtue of its object into an act ‘subjectively’ good or defensible as a choice” (VS 81). In summary, we can speak generally of certain types of conduct as gravely sinful without reference to one’s circumstances and intention in a specific case.
The Sunday Obligation
The Catechism provides us with various ways to categorize sins. One useful and traditional way of doing so is according to the commandments they violate (cf. no. 1853). Indeed, the Ten Commandments provide the framework for determining “grave matter” (cf. ibid., no. 1858).
The Church has from the beginning understood the Third Commandment (“keep holy the sabbath day”) as requiring attendance at Mass on Sundays and specified holy days. Failure to meet this requirement has been understood as constituting grave matter, given the fundamental importance of liturgical worship.
He who fails to hear Mass on the days of precept, unless he is hindered by some true impediment, commits a serious sin and does not fulfill the divine commandment to keep holy Sundays and holy days. This is also true of a person who does not provide the means to hear Mass for persons dependent upon him.
This obligation continues to be the “first precept” of the Church and continues to be required of all the faithful (cf. Catechism, nos. 2041-42). Those who deliberately fail to obey this precept “commit a grave sin” (Catechism, no. 2181).
In his Apostolic Letter Dies Domini (“The Day of the Lord”), Pope John Paul II provides profound teaching on the role of the Lord’s day in the Christian life. In doing so, the Holy Father provides a historical overview of the Sunday obligation (no. 46), and affirms that the duty to attend Mass on Sundays and holy days “has normally been understood as entailing a grave obligation” (no. 47).
The gravity of the Third Commandment is not limited to the Christian era. In the Old Testament, the violation of the Sabbath was considered by the Lord and by the Israelite people a capital offense (cf. Num. 16:32-36).
This raises the issue of whether a commandment to keep holy the “sabbath” can be applied to Sundays and even to holy days that may fall anytime during the week. The short answer is that the sabbath (“Saturday”) obligation was changed by the primitive Church to Sunday to commemorate the Resurrection of Christ from the dead on the first day of the week, as well as Pentecost Sunday, when the Spirit descended upon the Church. The Church received full, plenary authority from Christ (cf. Mt. 28:18), and thus has the authority to make laws and precepts for the good of the faithful, such that those who hear the Church hear Christ (cf. Lk. 10:16).
The early Christians endured fierce persecution because of their commitment to gather for the Eucharist each Sunday. Why would they risk death when they could worship God in the relative safety of their homes? Clearly the Christians in early centuries of Christendom considered their need to offer themselves in union with Christ at the holy sacrifice of the Mass to be more binding than even the instinct of self-preservation.
Scripture teaches us to work out our salvation with fear and trembling, for God is at work in us (Phil. 2:13). Our participation at Mass is the primary way we “work out” our salvation, as we partake in the once-for-all sacrifice of Christ—a sacrifice that is made present and applied to us (cf. Catechism, no. 1366). When we deliberately miss Mass on Sundays or holy days, “we turn our backs on Christ and on the process of our redemption. We refuse to carry out Christ’s command to ‘do this’ [Lk. 22:19] for the recalling and receiving of [H]im and [H]is salvation.”
Now that we’ve clarified that there are specific types of behavior that are gravely sinful, and that missing Mass on Sundays and holy days of obligation is one such type of behavior, some attention should be given to the factors that could diminish one’s culpability for missing Mass.
First, we need to realize that this is a sin of omission, not commission. In other words, this commandment requires us to do something (i.e., go to Mass) rather than refrain from some evil act (e.g., murder, adultery, theft, etc.). Accordingly, circumstances do play an important role in determining whether a person is able to “do” what this commandment requires. Church law surely recognizes that there may be instances where a person may not be able to attend Mass (cf. canons 1247-48; Dies Domini, no. 47). If such is the case, the failure to attend Mass, while most regrettable, is not sinful. This can be a recurring difficulty in missionary or remote rural areas where there is a scarcity of priests. Fr. Hardon provides some examples of circumstances that might excuse someone from attending Mass on Sunday:
The causes that might excuse from assisting at Sunday Mass are: physical impossibility which applies to those who are unable to hear Mass because they are sick, or who have no priest to say Mass for them; moral impossibility, when it would be very difficult to attend Mass, say because of the absolute necessity of fulfilling other grave duties; and the practice of charity, when Mass is sacrificed to remain at the bedside of the sick or give urgent assistance to someone in great need.
Fr. Hardon’s example of caring for someone who is sick also raises the issue of one’s intention or reason for choosing to miss Mass. The person who is performing such an act of charity is not directly choosing to miss Mass, but rather is impeded from choosing to attend by a sufficiently serious obligation. The situation would be different if one’s “duty” was merely an excuse to miss Mass (e.g., “Honey, I have to mow the lawn now”).
Assuming a person is not impeded from attending Sunday Mass, such failure is not a mortal sin unless the person making this decision has full knowledge and consent. In today’s climate, some Catholics do not know that Mass is a serious, “weekly” obligation, but rather consider it merely a good and pious thing to do on special occasions, such as Christmas, Easter, and perhaps weddings. While ignorance of the Sunday obligation is a mitigating factor, the fact remains that we are obliged to seek the truth which sets us free (cf. Jn. 8:32), rather than bank on a lack of knowledge. Indeed, the Catechism, quoting Vatican II, reminds us that one who “takes little trouble to find out what is true and good . . . is culpable for the evil he commits” (no. 1791).
Others are in situations where they have to rely on others to take them to Mass. Sadly, there are many Catholic school children who know that they are supposed to attend Mass on Sunday and who truly want to go, but their parents are lukewarm or nonpracticing, and fail in their duty to take their children to Mass. In such a scenario, the children do not fully will to miss Mass, and are not guilty of mortal sin (though their parents might be).
Splendor of the Truth
Missing Mass on Sundays and holy days of obligations is a common occurrence throughout the world, much like grave sins such as cohabitation before marriage, contraception, homosexual activity, and abortion. We must affirm that the frequency of occurrence does not lessen the gravity of the offense. Rather, this points to the development of a culture that does not recognize the sovereignty of God, and it also amplifies the need to provide better formation for the next generation of Catholics. And on an individual level, even apart from the culpability for any particular failure to attend Mass, the mere repetition of this sin leads to bad habits (“vices”) that are increasingly difficult to overcome and may even harden one’s heart against God and His Church.
We must also affirm that despite societal pressures to “conform” and to do “what’s right for you,” it is never a “good” choice for a Catholic to make a “personal” decision to miss Mass. Rather, at minimum, such a person is cutting himself or herself off from the primary means of our sanctification, and will find it even easier to miss Mass the following week.
Too often, the requirement to attend Mass on Sunday is seen as a rule or precept that is imposed on the faithful by the Catholic Church. We should strive to understand this requirement in the fuller, evangelical sense. The Eucharistic liturgy is the source and summit of our lives as Catholics, where we personally encounter Christ and abide in Him (cf. Jn. 15:1-10). The minimum requirement of the Church to participate in sacred liturgy is nothing other than a recipe for a life centered in Christ—the essence of growing in holiness. Assuredly, living the sacramental life—which includes (at least) weekly Mass, regular Confession, and daily prayer—will help us with God’s grace to root out the other moral difficulties in our lives and keep us oriented toward our true good: God Himself and eternal life with Him.