If There Are Cases of Justifiable Killing, Why Not Justifiable Adultery?

DIFFICULT MORAL QUESTIONS: Just as the bond of Christ’s love for his Church cannot be broken, neither can the bond of a Christian marriage.

Carl Heinrich Bloch (1834-1890), “Christ and the Woman at the Well”
Carl Heinrich Bloch (1834-1890), “Christ and the Woman at the Well” (photo: Public Domain / Public Domain)

Q. If not every act of killing is mortally sinful, why do we judge every act of adultery as such? We know Jesus said that when men and women divorce and remarry, they commit adultery. Scripture makes this clear. But what if a woman is abandoned by her husband, and remarries for the sake of her children — why is this still mortally sinful? She intends to help her children by contracting marriage in a situation where not contracting marriage could end in the children’s harm? Why isn’t this a lower grade sin or even not sinful at all? — Taylor

A. It is hard today to communicate effectively the reasons why divorce and remarriage are always gravely immoral, including under heartbreaking circumstances such as the ones you envisage. 

We have grown accustomed to hearing spectacular examples of marital infidelity, tragic cases of love betrayed and then of hearing of happy endings with second unions. 

When the Catholic Church repeats the scriptural teaching on the absolute indissolubility of Christian marriage, it can sound like a great unacceptable anachronism. Cardinal Gerhard Müller, the former prefect for the Congregation of the Doctrine of the Faith, says it well: “The doctrine of the indissolubility of marriage is often met with incomprehension in a secularized environment.”

But it is no anachronism. It is a truth as certain and relevant to Christian fulfillment as any in the Church’s canon — a truth that St. Paul refers to in Ephesians 5 as a “great mystery,” namely, that Christian marriage is a sign of Christ’s love for his Church

Catholics believe — and have died defending — that in virtue of its sacramentality, the strength of the marriage bond, brought into existence by the free exchange of spousal promises and completed by the spouses’ first act of intercourse, becomes as firm as Christ’s love. 

Therefore, just as the bond of Christ’s love for his Church cannot be broken, neither can the bond of a Christian marriage. 

You compared the morality of adultery with justifiable killing and asked why there is no such thing as justifiable adultery. The comparison, however, is flawed. Adultery should be referred not to generic killing but to the intentional killing of the innocent, which, like adultery, is judged always to be wrongful. 

Why are there never justifiable instances of adultery or killing the innocent? Because in both cases, the kind of act is greatly destructive of human good and incompatible with people’s salvation, and so the chosen behavior is never a light matter. 

To understand why this is the case, we need to turn to the nature of marriage in general, and then to consider Christian marriage.

Many today believe that what marriage brings into existence, beyond its legal status, is nothing more than an affective-moral bond, an intimate committed friendship founded upon the good will and affection of the spouses, and that the strength of any marriage is based upon the firmness of their affections, but that unfortunately sometimes these break down so that what makes the marriage is no longer present and so the marriage effectively no longer exists, and that divorce simply ratifies this reality. 

This is not the Catholic truth. Although marriage is brought into existence by human free choice — canon law uses the term “consent” (Canon 1057, 1-2) — what is brought into existence is more than a moral bond. (Cardinal Müller refers to the bond as “ontological.”) If it were merely a moral reality, then it would be subject to free choice. But once marriage is brought into existence, the bond is no longer subject to the will of the spouses. The permanence of the marriage bond is called its “indissolubility.” It’s not simply that spouses should not dissolve their marriage — they cannotdissolve it.

What accounts for this indissolubility? It is accounted for by two things: first by the kind of interpersonal communion marriage involves, and second, by the action of God.

Marriage’s full reality comes into existence though two choices on the part of the couple. Firstly, they morally consent to be married, which means to be in a one-flesh covenantal relationship. And secondly, they complete — consummate — the reality consented to by actualizing their one flesh union through marital intercourse.  

This one-flesh communion is unique among human relationships. Through it spouses form a unity that simultaneously unites them as persons and opens them to procreation. Saying the “two become one flesh” is not merely metaphorical (Genesis 2:24; Matthew 19:5). For purposes of procreation, maleness and femaleness need each other. Pope St. John Paul II refers to bodily complementarity as marriage’s “permanent foundation.” 

Marital indissolubility is also accounted for by the action of God. When couples marry, God too does something. They not only join themselves to each other, God also joins them: “What God has joined, let no man separate” (Mark 10:9). Jesus told us that marriage was like this “from the beginning” (Matthew 19:7-9, Mark 10.5-9; Genesis 1:27, 2:24). 

Canon law refers to this indissolubility as an “essential property” of marriage (1056). 

But marriage has been raised by Christ to the level of a sacrament, so that in the case of two baptized Christians everything that properly pertains to marriage and its intrinsic goods is grace-imparting and so assists the spouses to attain to the fullness of the reality that marriage signifies.

So the marriage bond between Christian takes on a much greater signification: Christ’s redeeming love for his Church. 

The indissolubility in Christian marriage by reason of the sacrament obtains “a special firmness” (1056), a firmness so enduring that consummated Christian marriage “can be dissolved by no human power and by no cause, except death” (1141). 

In the scenario you envisage, the woman who enters a second union while her husband still lives, although we feel great compassion for her tragic situation, is still married. Despite her husband’s infidelity, her marriage still images Christ’s love for his Church.

Should she fail to acknowledge this through attempting a second union, she would be doing something gravely wrong. The reality of the bond’s perdurance is of great significance for her and the world’s salvation, and by attempting a second union she would be setting herself against this reality. 

But should she reverence the truth that her marriage still exists despite her spouse’s faithlessness, she would witness to Jesus’s faithful love for his Church — a Church whose members, like her husband, are not infrequently faithless. 

This lucid witness to the indissolubility of marriage is greatly needed today. For it tells people — indeed, it speaks quite loudly — that marriage is more than what the world says it is. The world says it is a union that lasts only as long as fallen human love lasts. 

But her witness would say: Nay, marriage is about a kind of love that despite betrayal remains unyielding, and precisely because it neither yields to faithlessness nor sin — i.e., because it is indissoluble — it is a love that redeems. 

Yes, the great truth that this woman and all of us need to hear, and that faithful marriage witnesses to, is that indissoluble love, and only indissoluble love, is redeeming love. Redeeming. Liberating from sin. 

But not just that. (As if that were not enough.) Jesus’ indissoluble love accepted in faith invites us to a consummation greater than we can ask or imagine — a consummation in the kingdom between each of us and himself, a glorious completion of our persons in both the human and divine natures of Jesus’s resurrected person.

These truths can be difficult to believe. But they are no less true. They become believable because there are witnesses who recapitulate in their own lives a kind of love that images Jesus’s indissoluble love. 

Such is the gravity and greatness of marriage.