The 10 Commandments – The 5th: “You Shall Not Kill”

By Father Reginald Martin, O.P.


When we arrive at the Fourth Commandment, in which God ordered our ancestors to honor father and mother so they might enjoy a long life in the land He planned to give them, we approach the second tablet of God’s Law. These six commandments govern our relations with one another and reflect the immense value of God’s human creation. Because we are God’s creatures, we are part of a community ordained by God, a community in which each individual enjoys rights and shares responsibilities. In this community no one may take advantage of another, nor may one deprive another of her or his rights. The Protestant reformer, John Calvin, observed that charity “contains the sum of the second tablet.”


Biblical scholars hasten to point out the Scriptural language of the Fifth Commandment is very precise.

Murder is the correct translation, i.e. the unlawful killing of a member of the community. The commandment does not cover capital punishment, killing in a war, or the killing of animals for food; which is not to say the Old Testament is unconcerned with the ethical problems posed by these things. (The Oxford Bible Commentary, p. 82)


We talk about the “sacredness” of human life, but how often – if ever – have we considered the basis for this belief? In 1987, the Church’s Congregation for the Doctrine of the Faith issued an Instruction, Donum vitae, which teaches human life is holy because it is God’s gift.

…from its beginning it involves the creative action of God and it remains forever in a special relation with the Creator… God alone is the Lord of life from its beginning to its end: no one can under any circumstance claim for himself the right directly to destroy an innocent human being.


Scripture bears evidence to this when God punishes Cain for murdering his brother Abel. (Gen 4:8) He says, “The voice of your brother’s blood is crying to me from the ground, and now you are cursed from the ground….” Our Catechism summarizes the Biblical teaching when it states

The deliberate murder of an innocent person is gravely contrary to the dignity of the human being, to the golden rule, and to the holiness of the Creator. The law forbidding it is universally valid: it obliges each and everyone, always and everywhere. (CCC, #2261)

We might point out that Jesus expanded the prohibition in the Fifth Commandment to include anger. In his Sermon on the Mount he said, “You have heard that it was said to the men of old, ‘You shall not kill….’ But I say to you that every one who is angry with a brother shall be liable to judgment.” (Matt 5:21)


We may be surprised to discover the early Church writers have little to say about the Ten Commandments. An exception who proves the rule – and perhaps explains this silence – is St. John Chrysostom. He asks, when God said, “You shall not kill,” why did He not add, “because murder is a wicked thing?” He replies, “The reason was that conscience has already taught this. He (God) speaks thus, as if to those who know and understand the point.”


What the saint tells us is the commandments are nothing new; God gave them to Moses not as a revelation, but so we would have a permanent reference point. Too, the Law establishes a special and intimate relation between God and His human creation. However, the Law on Sinai does nothing more than set in stone what God engraved on our hearts on the sixth day of creation. God created us in His image; if we look like God, we ought to act like Him.

And here we might mention God always looks out for the most vulnerable of His creatures, a concern we see reflected particularly in the Fifth Commandment and the two that follow. A modern Scripture commentary remarks

The three commands on killing, adultery, and stealing together constitute something of a special group. Not only are they the most tersely expressed commands, but also they all address the ways in which vulnerable persons in community are assaulted, diminished, and destroyed. Such actions, condemned in these commands, are all acts of uncurbed power, which fails to recognize that the perpetrator and the victim share a commonality that preclude destructiveness. (The New Interpreter’s Bible, p. 851)


Our Catechism points out we must also keep in mind the special relations that bind us to one another. “The fifth commandment forbids direct and intentional killing as gravely sinful,” and the text continues,

Infanticide, fratricide, parricide, and the murder of a spouse are especially grave crimes by reason of the natural bonds which they break. Concern for eugenics or public health cannot justify murder, even if commanded by public authority. (#2268)


The closeness of relations increases our responsibility toward certain individuals in our lives, but distance does not excuse us from a lack of regard for the good of others. The Catechism warns, “The fifth commandment forbids doing anything with the intention of indirectly bringing about a person’s death… [such as] exposing a person to mortal danger without grave reason, as well as refusing assistance to a person in danger.” (#2269)

As examples, the Catechism cites failing to offer relief, to the extent we can, to victims of famine or other natural disasters. The text is particularly harsh in its judgment of cruel and totalitarian political civil leaders. “Those whose usurious and avaricious dealings lead to the hunger and death of their brethren in the human family indirectly commit homicide, which is imputable to them.”


Painful though this may be, we must now turn our attention to some of the acts condemned by the Fifth Commandment. The first of these is intentional homicide, which our Catechism defines as “direct and intentional killing.” (#2268) The text, calling our attention back to Cain’s murder of his brother, remarks, “The murderer and those who cooperate voluntarily in murder commit a sin that cries out to heaven for vengeance.”


What shall we say about death that occurs when an individual is protecting him or herself from an attack? In this case we need to consider what the Church’s moral theologians name the Principle of Double Effect. St. Thomas Aquinas explains this very simply when he writes, “The act of self-defense can have a double effect: the preservation of one’s own life; and the killing of the aggressor… The one is intended, the other is not.” (ST, II-II, 64.7)

Lest this appear a hypocritical ruse for Christians to engage in violent behavior, we must stress the unintended nature of the second outcome.


At present, few issues are so divisive as abortion. Our Catholic faith stands unshaken in its defense of the unborn, and the Catechism teaches

Human life must be respected and protected absolutely from the moment of conception. From the first moment of his existence, a human being must be recognized as having the rights of a person – among which is the inviolable right of every innocent being to life. (#2270)

Lest we imagine this solely a modern teaching, the Catechism stresses a continuity of tradition extending back to the early days of our faith. The Didache, sometimes called “The Teaching of the Twelve Apostles,” is the earliest example of a Catechism. It dates to the late First or early Second Century, and states, “You shall not kill the embryo by abortion and shall not cause the newborn to perish.”


Earlier in this reflection we mentioned Donum vitae, the Instruction from the Congregation for the Doctrine of the Faith. When it considers the rights of unborn children, the Instruction is absolutely clear

The inalienable rights of the person must be recognized and respected by civil society and the political authority. These human rights depend neither on single individuals nor on parents; nor do they represent a concession made by society and the state; they belong to human nature and are inherent in the person by virtue of the creative act from which the person took his origin.The moment a positive law deprives a category of human beings of the protection which civil legislation ought to accord them, the state is denying the equality of all before the law….

Once again we are dealing with rights conferred by Natural Law, the reality John Chrysostom believed “conscience has already taught.” Unfortunately, we can no longer share Chrysostom’s optimism, for the interminable legal debates we presently observe prove lawmakers apparently do not “know and understand the point.”


The dictionary defines euthanasia as “the act of killing an individual for reasons considered to be merciful.” OurCatechism is somewhat more specific, and identifies the individuals to be killed as “handicapped, sick, or dying persons.” (#2277) Euthanasia is sinful for the same reason abortion is sinful: it violates the rights of an individual. On its surface, euthanasia may seem quite attractive, as it offers a solution to human suffering, but our Catechismobserves

…an act or omission which…causes death in order to eliminate suffering constitutes a murder gravely contrary to the dignity of the human person and to the respect due to the living God, his Creator. The error of judgement into which one can fall in good faith does not change the nature of this murderous act….


Individuals and families often face difficult decisions regarding medical care when extreme age or serious illness threatens a life. How much care is required? If it is withheld, and death results, does this constitute euthanasia? Here a careful judgment must be made between the means and the desired end. Once again, our Catechism offers wise counsel

Discontinuing medical procedures that are burdensome, dangerous, extraordinary, or disproportionate to the expected outcome can be legitimate; it is the refusal of “over-zealous” treatment. Here one does not will to cause death; one’s inability to impede it is merely accepted. (#2278)


After our reflections on taking the lives of others, we should not be surprised to learn the Fifth Commandment forbids taking one’s own life, and for the same reasons. St. John writes, “In this is love, not that we loved God, but that he loved us….” (1 Jn 4:10) God’s love enables us to love God, and then to love His creatures. We, ourselves, are the first of God’s creatures we learn to love. This is not mindless selfishness; it is respect for God’s creation, and our Catechism observes, “Love toward oneself remains a fundamental principle of morality.” (#2264)

At the same time, we must remember our life is a gift given in trust. We do not exercise complete control over it; God expects us to give it back. Thus, the Catechism teaches

Everyone is responsible for his life before God who has given it to him. It is God who remains the sovereign Master of life. We are obliged to accept life gratefully and preserve it for his honor and the salvation of our souls. We are stewards, not owners, of the life God has entrusted to us. It is not ours to dispose of. (#2280)


Here we need to remark that while the Fifth Commandment forbids murder, and, thus, the taking of our own life, we must leave to God’s mercy the judgment of those who have committed suicide. At the very beginning of our moral education we learn that guilt may be increased or decreased by circumstances surrounding our actions. TheCatechism teaches, “Grave psychological disturbances, anguish, or grave fear of hardship, suffering or torture can diminish the responsibility of the one committing suicide.” (#2282) And the text continues,

We should not despair of the eternal salvation of persons who have taken their own lives. By ways known to him alone, God can provide the opportunity for salutary repentance. The Church prays for persons who have taken their own lives. (#2283)


Because life is God’s gift, we must protect it. In concrete, personal terms, this means taking care of our physical and mental health, and practicing the virtue of temperance in our consumption of food and drink. We might not imagine safe driving to fall under the shadow of the Fifth Commandment, but such caution protects our own lives and safeguards the lives of those with whom we share the human community.

At the same time, the Fifth Commandment warns us to avoid making our bodies objects of worship. God has created us to share the world with one another, and excessive zeal to stand out breaks down the bonds that ought to unite us.


“Prince of Peace” was one of the Old Testament titles to be conferred on the Messiah, and in the Church’s liturgy for Christmas Eve, the reading from the Martyrology speaks of Jesus’ birth “in the forty-second year of the rule of Octavian Augustus; in the sixth age of the world, when the whole world was at peace.” Such a Messiah and such a world may seem no more than vain hopes today, but “by recalling the commandment, ‘You shall not kill,’ our Lord asked for peace of heart and denounced murderous anger and hatred as immoral.” (CCC, #2302)

This suggests, correctly, that peace must begin within individual hearts, and challenges Christians to make Christ’s Kingdom of Peace a reality that will guide all nations. Toward that end, “…the Church insistently urges everyone to prayer and to action so that the divine Goodness may free us from the ancient bondage of war.” (CCC, #2307)


Regrettably, that day seems quite far off, so Church teaching anticipates the need for nations to use force, at least occasionally, to defend themselves if peace efforts have failed. However, the use of such force must be carefully considered, and the outcomes weighed. The threat to a nation must be certain, and before resorting to military force, all non-violent means to resolving a difficulty must have been exhausted. Moreover, the anticipated military action must not threaten greater harm to the nation than the ills to be eradicated.


And if war should come, the Fifth Commandment remains a part of our original union with God. The Catechismquotes a document of Vatican II, Gaudium et Spes, when it states

The Church and human reason both assert the permanent validity of the moral law during armed conflict. “The mere fact that war has regrettably broken out does not mean that everything becomes licit between the warring parties.” (#2312)Non-combatants, wounded soldiers, and prisoners must be respected and treated humanely. (#2313)

These observations lead us back to the beginning of our reflection, where we considered that because we are God’s creatures, we are part of a community. The outcomes of war may inevitably threaten or damage this community, but the leaders of warring nations must remember each of us is God’s creation, and none of us may take advantage of another.

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