Human life is sacred
“Human life is sacred because from its beginning it involves the creative action of God and it remains forever in a special relationship with the Creator, who is its sole end . . . no one can under any circumstance claim for himself the right directly to destroy an innocent human being” (Catechism, 2258).
Man is created in the image and likeness of God (cf. Gen 1:26-27). Each human being is the only creature in this world whom God loves for its own sake. We are destined to know and love God eternally. Here lies the ultimate foundation of the sacredness and dignity of human life and, in its moral dimension, of the commandment “Thou shalt not kill.” The encyclical Evangelium vitae (1995), which offers a beautiful meditation on the unique value of human life and each person’s call to eternal life and communion with God, stresses that “the sacredness of human life gives rise to its inviolability” (no. 40). After the flood, in the covenant made with Noah, the fact that man is created in God’s image is clearly established as the basis for the condemnation of murder (cf. Gen 9:6).
The fact that human life has been placed in the power of our hands requires knowing how to administer it in collaboration with God. This requires an attitude of love and service, and not of arbitrary dominion: it is a ministerial, not absolute lordship, a reflection of the unique lordship of God.
The book of Genesis presents the abuse of human life as a consequence of original sin. Yahweh always shows himself to be the protector of life: even that of Cain, after having killed his brother Abel. No one may take justice into his own hands, and no one may arrogate to himself the right to dispose of the life of their neighbour (cf. Gen 4:13-15).
Although this commandment refers specifically to human life, it reminds us of the need to care for other living creatures and our common home. In the encyclical Laudato sí (2015) we read: “when our hearts are authentically open to universal communion, this sense of fraternity excludes nothing and no one. It follows that our indifference or cruelty towards fellow creatures of this world sooner or later affects the treatment we mete out to other human beings. We have only one heart, and the same wretchedness which leads us to mistreat an animal will not be long in showing itself in our relationships with other people. Every act of cruelty towards any creature is ‘contrary to human dignity’” (no. 92).
This commandment, like the rest, finds its full meaning in Christ, and specifically in the Sermon on the Mount: “You have heard that it was said to those of old, ‘You shall not kill,’ and whoever kills shall be liable to judgment. But I say to you, whoever is angry with his brother shall be liable to judgment, and whoever insults his brother shall be liable to judgment before the Sanhedrin, and whoever curses him shall be liable to hellfire. If, therefore, when you bring your gift to the altar, you remember that your brother has something against you, leave your gift there before the altar, go and be reconciled to your brother first, and then come back and present your gift” (Mt 5:21-24). “The deepest element of God's commandment to protect human life is the requirement to show reverence and love for every person and the life of every person.”
Moral duty to preserve life and health
Human life should be received as a precious gift from God to be protected and preserved. The Catechism teaches that we must care for our health in a reasonable way, always taking into account the needs of others and the common good (no. 2288). At the same time, it reminds us that it is not an absolute value. Christian morality is opposed to a neo-pagan conception which promotes the cult of the body, and which can lead to the undermining of human relationships (no. 2289).
“The virtue of temperance disposes us to avoid every kind of excess: the abuse of food, alcohol, tobacco, or medicine. Those incur grave guilt who, by drunkenness or a love of speed, endanger their own and others’ safety on the road, at sea, or in the air” (no. 2290). Hence the use of drugs is also a serious offence, because it causes serious damage to one’s health (no. 2291).
The letter Samaritanus bonus (2020) points out that the development of medicine helps us in our duty to preserve and care for human life and health. At the same time it reminds us of the need to use all diagnostic and therapeutic possibilities with a wise capacity for moral discernment, avoiding anything that could be disproportionate or even dehumanising.
The Church teaches that organ donation for transplants is legitimate and can be an act of charity, if it is a completely free and gratuitous action, and respects the order of justice and charity. “A person can only donate something of which he can deprive himself without serious danger or damage to his own life or personal identity, and for a just and proportionate reason. It is obvious that vital organs can only be donated after death.”
The fifth precept forbids killing a human being. It also forbids striking, wounding or doing any unjust bodily harm to oneself or to one’s neighbours, as well as offending them with insulting words or wishing them harm. This commandment also forbids killing oneself (suicide). The encyclical Evangelium vitae dedicates the third part to dealing with attacks on life, taking up the previous moral tradition. This section solemnly condemns voluntary manslaughter, abortion and euthanasia.
“The fifth commandment forbids direct and intentional killing as gravely sinful. The murderer and those who cooperate voluntarily in murder commit a sin that cries out to heaven for vengeance (cf. Gen 4:19)” (Catechism, 2268). Evangelium vitae has formulated in a definitive and infallible way the following negative norm: “by the authority which Christ conferred upon Peter and his Successors, and in communion with the Bishops of the Catholic Church, I confirm that the direct and voluntary killing of an innocent human being is always gravely immoral. This doctrine, based upon that unwritten law which man, in the light of reason, finds in his own heart (cf. Rom 2:14-15), is reaffirmed by Sacred Scripture, transmitted by the Tradition of the Church and taught by the ordinary and universal Magisterium”.
This condemnation does not exclude the possibility of legitimate self-defence, which sometimes presents a real paradox. As Evangelium vitae also teaches, “legitimate defence can be not only a right but a grave duty for someone responsible for another's life, the common good of the family or of the State. Unfortunately it happens that the need to render the aggressor incapable of causing harm sometimes involves taking his life” (no. 55).
“Human life must be respected and protected absolutely from the moment of conception” (Catechism, 2270). Therefore, “direct abortion, that is, abortion willed as an end or as a means, always constitutes a grave moral disorder, since it is the deliberate killing of an innocent human being.” “No circumstance, no purpose, no law whatsoever can ever make licit an act which is intrinsically illicit, since it is contrary to the Law of God which is written in every human heart, knowable by reason itself, and proclaimed by the Church.”
Today, in many countries, abortion is seen as a right and an indispensable means to continue advancing women’s reproductive health. This makes it difficult to understand the teaching of the Church here and is one of the reasons why many people resort to these interventions with an ignorance that is often invincible. Moreover, when faced with an unwanted pregnancy, social and family pressure can be so great that the personal responsibility of the woman seeking an abortion is often diminished.
All initiatives that help mothers to continue with their pregnancies, especially when they face special difficulties, are therefore to be commended. The state has a major role to play in this area, as it means defending a particularly vulnerable population. The work being done to provide adequate information on the reality of abortion and its negative psychological and existential consequences – sometimes serious – for those who choose this option is also very commendable.
Suicide and euthanasia
Some mistakenly think that the prohibition not to kill refers only to others, and that Christianity should not be contrary to suicide, at least in some circumstances, claiming that there is no explicit condemnation of this in Sacred Scripture. However, as Evangelium vitae (no. 66) reminds us, “suicide is always as morally objectionable as murder. The Church's tradition has always rejected it as a gravely evil choice.” The Catechism stresses that “it is gravely contrary to the just love of self. It likewise offends love of neighbor because it unjustly breaks the ties of solidarity with family, nation, and other human societies to which we continue to have obligations. Suicide is contrary to love for the living God” (no. 2281). It is quite another thing to accept one’s own death in order to save the life of another, which is an act of heroic charity.
It is true that certain psychological, cultural and social conditioning factors can attenuate or even annul the subjective responsibility of suicide, and the Church commends to God the souls of those who have committed this extreme act. However, this does not mean that the choice to intentionally bring about one’s own death is justified.
In recent decades, euthanasia has gained ground in many countries, where a third party performs the lethal action, at the request of the person concerned. Euthanasia in the true and proper sense is to be understood as an action or omission which by its nature and intention causes death in order to eliminate any pain. The Church has always taught that it is “a grave violation of the law of God, since it is the deliberate and morally unacceptable killing of a human person . . . Depending on the circumstances, this practice involves the malice proper to suicide or murder.” This is one of the consequences, seriously contrary to the dignity of the human person, which hedonism and the loss of the Christian meaning of pain can lead to.
It is important to distinguish euthanasia from other actions carried out in the context of appropriate medical care at the end of life, such as the interruption of certain treatments, which are considered at a certain point to be extraordinary or disproportionate to the objectives sought. It is also distinct from so-called “palliative sedation,” which is a therapeutic tool for some terminal situations in which ordinary treatments are not sufficient to spare the patient severe suffering. Sometimes it is not easy to determine the most appropriate choices. That is why the letter Samaritanus bonus offers some criteria that can help people make good decisions.
In relation to abortion and euthanasia it is necessary to remember that respect for life must be recognised as the boundary that no individual or state activity can violate. The inalienable right of every innocent human person to life is a constitutive element of civil society and its legislation, and should be recognised and respected as such by both society and political authorities (cf. Catechism, 2273).
Hence, “there is no obligation in conscience to obey such laws [permitting abortion]; instead there is a grave and clear obligation to oppose them by conscientious objection.”
The death penalty
For centuries, the death penalty has been justified as an effective means to ensure the defence of the common good, and even as a way to restore justice in cases of grave crimes. The Magisterium of the Church has progressively evolved in its teaching here, taking into account the ever-greater possibilities of protecting the common good of citizens through appropriate systems of detention. The present formulation in the Catechism (no. 2267) views the death penalty as inadmissible, since it is an attack on the inviolability and dignity of the human person, and states that the Church is committed to its total abolition throughout the world.
Kidnapping and hostage-taking are morally wrong, since it means treating people only as means to various ends, depriving them unjustly of their freedom. Terrorism and torture are also gravely contrary to justice and charity.
“Except when performed for strictly therapeutic medical reasons, directly intended amputations, mutilations, and sterilizations performed on innocent persons are against the moral law” (Catechism, 2297).
After mentioning offences against the body, the Catechism in its explanation of the fifth commandment refers to “offences against the soul,” and specifically to scandal. Jesus condemned this when preaching to his disciples: “Whoever scandalises one of these little ones who believe in me, it is better for him that a millstone be hung around his neck and he be cast into the sea” (Mt 18:6). Scandal is an “attitude or behavior which leads another to do evil.” It is a serious offence, because it leads, either by action or omission, to others committing a sin. Scandal can be caused by unjust comments, by the promotion of immoral shows, books and magazines, by following fashions contrary to modesty, etc.
The encyclical Fratelli tutti (2020) invites us to foster “a fraternal openness that allows us to acknowledge, appreciate and love each person, regardless of physical proximity, regardless of where he or she was born or lives” (no. 1). This fraternity is capable of founding true social and international peace.
“Blessed are the peacemakers, for they shall be called children of God” (Mt 5:8). It is characteristic of the spirit of divine filiation to be sowers of peace and joy. “Peace cannot be attained on earth without safeguarding the goods of persons, free communication among men, respect for the dignity of persons and peoples, and the assiduous practice of fraternity . . . It is the work of justice (cf. Is 32:17) and the effect of charity” (Catechism, 2304).
Human history has seen, and continues to see, so many wars that promote destruction and hatred. Although sometimes presented as unavoidable, they are always “false answers, which do not solve the problems they are intended to overcome and which in the end only add new factors of destruction to the fabric of national and universal society.” “Because of the evils and injustices that accompany all war, the Church insistently urges everyone to prayer and to action so that the divine Goodness may free us from the ancient bondage of war (cf. Second Vatican Council, Gaudium et Spes, 81,4)” (Catechism, 2307). The Catechism teaches that there is a “legitimate defence by military force.” But “the gravity of such a decision subjects it to rigorous conditions of moral legitimacy” (Catechism, 2309). And it stresses: “It is necessary at the same time that: the damage inflicted by the aggressor on the nation or community of nations must be lasting, grave, and certain; all other means of putting an end to it must have been shown to be impractical or ineffective; there must be serious prospects of success; the use of arms must not produce evils and disorders graver than the evil to be eliminated. The power of modern means of destruction weighs very heavily in evaluating this condition.”
The arms race, “far from eliminating the causes of war, risks aggravating them. Spending enormous sums to produce ever new types of weapons impedes efforts to aid needy populations” (Catechism, 2315). The arms race “is an utterly treacherous trap for humanity, and one which ensnares the poor to an intolerable degree” (Second Vatican Council, Gaudium et Spes, 81). The authorities have the right and the duty to regulate the production of and trade in arms (cf.Catechism, 2316).
Catechism of the Catholic Church, 2258-2330.
John Paul II, Evangelium vitae, 25 March 95, chapter III.
 Cf. Second Vatican Council, Gaudium et spes, 24.
 Saint John Paul II, Evangelium vitae, 25 March 95, 52.
 Ibid., 41.
 Cf. Saint John Paul II, Discourse, 22 June 1991, 3; Catechism, 2301.
 Ibid., 4.
 It also “forbids doing anything with the intention of indirectly bringing about a person's death. The moral law prohibits exposing someone to mortal danger without grave reason, as well as refusing assistance to a person in danger” (Catechism, 2269).
 Saint John Paul II, Evangelium vitae, 57.
 Ibid., 62.
 Ibid., 62. So great is the gravity of the crime of abortion that the Church sanctions this crime with the canonical penalty of excommunication latae sententiae (cf. Catechism, 2272).
 However, “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” (Catechism, 2283).
 Saint John Paul II, Evangelium vitae, 65.
 “These human rights depend neither on single individuals nor on parents; nor do they represent a concession made by society and the State: they pertain to human nature and are inherent in the person by virtue of the creative act from which the person took his or her origin . . . the moment a positive law deprives a category of human beings of the protection which civil legislation must accord them, the State is denying the equality of all before the law. When the State does not place its power at the service of the rights of each citizen, and in particular of the more vulnerable, the very foundations of a State based on law are undermined” (Congregation for the Doctrine of the Faith, Donum vitae, 22 February 1987, 3).
“What crimes are committed in the name of justice! If you were a dealer in fire-arms and someone offered to buy a gun from you, so that he might use the weapon to kill your mother, would you sell it to him? — Yet, wasn't he ready to pay you a just price for it? University professor, journalist, politician, diplomat: reflect” (Saint Josemaría, The Way, 400).
 Saint John Paul II, Evangelium vitae, 73.
 Catechism, 2284.
 “They are guilty of scandal who establish laws or social structures leading to the decline of morals and the corruption of religious practice, or to ‘social conditions that, intentionally or not, make Christian conduct and obedience to the Commandments difficult and practically impossible’ (Pius XII, Discourse, 1 June 1941)” (Catechism, 2286).
 Cf. Saint Josemaría, Christ Is Passing By, 124.
 Pope Francis,Fratelli tutti, 255.
 These are the traditional elements in the so-called “just war” doctrine. “The evaluation of these conditions for moral legitimacy belongs to the prudential judgment of those who have responsibility for the common good” (Catechism, 2309). Moreover, “one is morally bound to resist orders that command genocide” (Catechism, 2313).
 Pope Francis, Fratelli tutti, 256-262.