This post is part of’s commentary on the Catechism of the Catholic Church: Part Three, Section One, Chapter One, Article Eight (nos. 1846-1876).

In the Catholic tradition, sin is described as a stain or contagion, an interior disposition of selfishness, a disordered heart,  a misguided will, an external act that violates a law or rule, a rejection of God, a power or force of evil, and a kind of social disorder. Yet the Catechism offers a clear overview of the most salient distinctions in contemporary sin-talk.

This section of the Catechism builds on an earlier section dedicated to The Fall and the Reality of Sin (385-421). There one finds an extended treatment of the doctrine of original sin, which is called the “reverse side” of the Good News of Jesus Christ (389).  The doctrine of original sin is rooted in an interpretation of the Genesis creation narratives at the beginning of the Bible. While God created out of love and self-gift, the state of grace for the first human creatures is broken by their disobedience and abuse of freedom (397-8). This first sin, which could be called a personal sin of the first parents, then becomes “original sin,” which is “a sin with which we are all born afflicted,” (403) and is thus not to be collapsed with personal sin for contemporary Christians. “Original sin is called ‘sin’ only in an analogical sense: it is a sin ‘contracted’ and not ‘committed’—a state and not an act” (404). As a result of the fall, human nature is wounded and the state of original justice is broken. While original sin does not have the character of personal fault (405), the Church teaches that no one is free from the effects of the fall. Indeed, the Compendium of the Social Doctrine of the Church reasserts this claim in relation to the reality of social divisions today: “At the root of personal and social divisions, which in differing degrees offend the value and dignity of the human person, there is a wound which is present in man’s inmost self” (116). The doctrine of original sin, or the acceptance of the claim that the human person is wounded by sin, does not negate the Church’s teaching regarding the dignity of the human person. These ideas can coexist: human beings are created in the image and likeness of God and human beings are wounded by sin. In Church teachings, the universality of sin leads to the claim of the universality of salvation. All are sinners in need of God’s grace. And God’s grace is available to all.

Keeping in mind this background, the Catechism’s treatment of the category of Sin under Part Three: Life in Christ begins in a similar position by affirming that the Gospel (“Good News”) proclaims the revelation of Jesus Christ as God’s mercy to sinners (1846). One of the overwhelming messages of Jesus’ earthly ministry was the availability of God’s grace and the forgiveness available for human sins. But one important first step towards reception of forgiveness is the honest acknowledgement of one’s sins. The Catechism quotes 1 John, in which the metaphor of light and darkness conveys the absence or presence of sin:

“God is light and in him there is no darkness at all. If we say that we have fellowship with him while we are walking in darkness, we lie and do not do what is true; but if we walk in the light as he himself is in the light, we have fellowship with one another, and the blood of Jesus his Son cleanses us from all sin. If we say that we have no sin, we deceive ourselves, and the truth is not in us. If we confess our sins, he who is faithful and just will forgive us our sins and cleanse us from all unrighteousness. If we say that we have not sinned, we make him a liar, and his word is not in us” (1 Jn 1:5b-10).

Sin has profound effects on our relationship to God, self, and others in the human community. Sin is first of all an “offense against God,” for it involves a rejection of God’s love for us (1850). But sin is also a failure of authentic self-love, though this failure is more often characterized in the tradition as pride, self-exaltation, or disobedience (1850). Additionally, sin ruptures human relationships and threatens the common good. When describing different kinds of sins, the Catechism notes that there are different kinds of classifications of sins in the tradition:

 “Sins can be distinguished according to their objects, as can every human act; or according to the virtues they oppose, by excess or defect; or according to the commandments they violate. They can also be classed according to whether they concern God, neighbor, or oneself; they can be divided into spiritual and carnal sins, or again as sins in thought, word, deed, or omission” (1853).

Thus, sin can include interior dispositions or external acts; sins can also include the failure to act. While this might seem confusing, one of the important things to note in this treatment of sin is that sin involves the use of human freedom and a rejection of God’s will. But some sins are more serious than others. The Catechism explains that some sins, called “mortal” sins, are more grave than so-called “venial” sins—although no sins should be taken lightly.

Mortal sin involves a “grave violation of God’s law” and turns the person away from God. For a sin to be mortal, three conditions must be met: “Mortal sin is sin whose object is grave matter and which is also committed with full knowledge and deliberate consent” (1857).  Thus mortal sin is when one freely chooses to do something one knows to be gravely wrong; as a result, one ruptures one’s relationship with God. Mortal sin “causes exclusion from Christ’s kingdom” if one does not repent (1861).

Venial sin is a sin that is not mortal sin; that is, it involves less serious matter, or the lack of full knowledge or the lack of complete consent (1862). Venial sin harms the person’s relationship with God, but “it does not break the covenant with God” (1863).

The Catechism’s treatment of sin ends with a section on The Proliferation of Sin (1865-1869), which describes how habits of sin become vices (for the flip side of vices, see “virtues”).  For this reason, even venial sins that do not completely rupture our relationship with God are not to be taken lightly. The task of discipleship involves honest admissions of our failures to love God, self, and others. And yet the Catechism acknowledges that while “sin is a personal act” (1868), these personal acts “give rise to social situations and institutions that are contrary to the divine goodness” (1869). The proliferation of personal sins thus leads to “structures of sin.” But these structures of sin are rooted in personal sin. The Compendium of the Social Doctrine of the Church affirms this way of thinking:

“The mystery of sin is composed of a twofold wound, which the sinner opens in his own side and in the relationship with his neighbor. That is why we can speak of personal and social sin. Every sin is personal under a certain aspect; under another, every sin is social, insofar as and because it also has social consequences. In its true sense, sin is always an act of the person, because it is the free act of an individual person and not properly speaking of a group or community. … It is not, however, legitimate or acceptable to understand social sin in a way that, more or less consciously, leads to a weakening or the virtual cancellation of the personal component by admitting only social guilt and responsibility. At the bottom of every situation of sin there is always the individual who sins” (117).

At stake here is the insistence that the root of sin involves personal freedom; thus, in order to be sin, social sin must involve the choice to participate in structures that cause harm or that frustrate the common good.  To the extent that the Catechism describes sin as a personal act, sin-talk in the Christian tradition is aligned with responsibility in the moral life. We are even responsible for the sins of others “when we cooperate in them by participating directly and voluntarily in them; by ordering, advising, praising, or approving them; by not disclosing or not hindering them when we have an obligation to do so; and by protecting evil-doers” (1868).

Sin is admittedly a thorny and confusing category in moral theology, for it involves the interpretation of Scripture, reflection on human experiences, explicit connection to central doctrines of the faith (like “salvation through Christ”), the sacraments, and personal prayer, among other aspects of the moral life. Theological discourse on sin has blossomed in recent decades as many seek to more fully articulate what this important category reveals about God and about the human condition. One area of ongoing investigation involves engagement with knowledge from the natural sciences in order to better understand the origin of the universe and what this might disclose for Christian beliefs about creation and sin.  Other areas of concern include the problem of suffering—especially the dehumanizing suffering of the poor all over the world—in relation to traditional notions of personal sin. Some scholars have begun to ask whether sin is a gendered experience (i.e. do men “sin” differently than women?) while others wonder how to best talk about individual complicity in complex social evils (like globalization, consumerism, or threats to environmental sustainability). Some wonder about how to talk about ecclesial dimensions of sin in the wake of the sexual abuse crisis. Some moral theologians emphasize the problem of moral blindness—our failure to recognize sinfulness; while others argue that the tradition has overemphasized the sinful nature of the human person and what is needed is a correction that today confirms the essential goodness of the human person as created by a loving God. Interdisciplinary studies (for example, connecting theology to psychology, sociology, and/or pastoral studies) and comparative approaches (analyzing “sin-talk” in other religious traditions or cultures) have widened the discourse considerably as well.