THE FIFTH COMMANDMENT

You shall not kill (Exodus 20:13; Deut. 5:17).

You have heard that the ancients were told, 'You shall not commit murder' and 'Whoever commits murder shall be liable to the court.' But I say to you that everyone who is angry with his brother shall be guilty before the court; and whoever says to his brother, 'You good-for-nothing,' shall be guilty before the supreme court; and whoever says, 'You fool,' shall be guilty enough to go into the fiery hell (Matthew 5:21-22).

Human life is sacred because from its beginning it involves the creative action of God and it remains for ever in a special relationship with the Creator, who is its sole end. God alone is the Lord of life from its beginning until its end: no one can under any circumstance claim for himself the right directly to destroy an innocent human being (CDF, instruction, Donum vitae, intro. 5).

I. Respect for Human Life – The witness of sacred history
In the account of Abel's murder by his brother Cain (Gen 4:8-12), Scripture reveals the presence of anger and envy in man – consequences of original sin – from the earliest days of human history. And because of sin, man has become the enemy of his fellow man. God declares the wickedness of this fratricide: "What have you done? the voice of your brother's blood is crying to me from the ground, and now you are cursed from the ground, which has opened its mouth to receive your brother's blood from your hand" (Gen 4:10-11).

The covenant between God and mankind is interwoven with reminders of God's gift of human life and man's murderous violence: “Surely I will require your lifeblood; from every beast [that sheds your blood] I will require it. And from every man, from every man's brother I will require the life of man. Whoever sheds man's blood, by man his blood shall be shed, for in the image of God He made man (Genesis 9:5-6).

The Old Testament always considered blood a sacred sign of life (Lev. 17:14).

Scripture specifies the prohibition contained in the fifth commandment: “Do not slay the innocent and the righteous” (Ex 23:7). The deliberate murder of an innocent person is gravely contrary to the dignity of the human being, to the second great commandment, and to the holiness of the Creator. The law forbidding it is universally valid: it obliges each and everyone, always and everywhere.

In the Sermon on the Mount, the Lord recalls the commandment, "You shall not kill" (Matt 5:21), and adds to it the prohibition of anger, hatred, and vengeance – which in God’s sight are forms of murder. Going further, Christ asks his disciples to turn the other cheek, to love their enemies (Matt 5:22-39, 44). As an example of not murdering through anger, hatred, or vengeance, when being reviled and tortured, Jesus did not revile in return or utter threats, He told Peter to leave his sword in its sheath, and He sought God’s forgiveness for His tormentors (1 Pet 2:21-23; Matt 26:52; Luke 23:34).

Legitimate defense
The legitimate defense of persons and societies is not an exception to the prohibition against the intentional murder of the innocent. Proper care for oneself and those under one’s care remains a fundamental principle of morality. Therefore, someone who defends his life or the well-being of the community is not guilty of murder even if he is forced to deal his aggressor a lethal blow.

“If a man in self-defense uses more than necessary violence, it will be unlawful: whereas if he repels force with moderation, his defense will be lawful.... Nor is it necessary for salvation that a man omit the act of moderate self-defense to avoid killing the other man, since taking care of oneself is important to the well-being of the larger community. Therefore, legitimate defense can be a grave duty for someone responsible for the life or lives of others. Preserving the common good requires rendering the unjust aggressor unable to inflict harm. To this end, those holding legitimate authority have the right to repel by armed force aggressors against the civil community entrusted to their charge” (Thomas Aquinas).

Capital Punishment
The State's effort to contain the spread of behaviors injurious to human rights and the fundamental rules of civil coexistence corresponds to the requirement of watching over the common good. Legitimate public authority has the right and duty to inflict penalties commensurate with the gravity of the crime. The primary scope of the penalty is to redress the disorder caused by the offense. When his punishment is voluntarily accepted by the offender, it takes on the value of expiation (to atone or make amends for one’s wrong). Moreover, punishment, in addition to preserving public order and the safety of persons, has a medicinal scope: as far as possible it should contribute to the correction of the offender (Lk 23:40-43.).

The traditional teaching of the Church does not exclude – presupposing full ascertainment of the identity and responsibility of the offender – recourse to the death penalty, when this is the only practicable way to defend the lives of community members against the aggressor. “If, instead, bloodless means are sufficient to defend against the aggressor and to protect the safety of persons, public authority should limit itself to such means, because they better correspond to the concrete conditions of the common good and conform more to the dignity of the human person. Today, given the means at the State's disposal to effectively repress crime by rendering harmless the one who has committed it, without depriving him of the possibility of redeeming himself, it is rare, if not practically non-existent that an offender must be put to death” (John Paul II, Evangelium vitae 56).

Intentional homicide
The fifth commandment forbids direct and intentional killing. The murderer and those who cooperate voluntarily in murder commit a sin that cries out to heaven for vengeance (Gen 4:10).

Infanticide (murdering children), fratricide (siblings), parricide (parents), and the murder of a spouse are especially grave crimes by reason of the natural bonds which they break. Concern for eugenics (the science of using controlled breeding to increase the occurrence of desirable heritable characteristics in a population)  or public health cannot justify any murder, even if commanded by public authority.

The fifth commandment 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 prohibits refusing assistance to a person in mortal danger.

The acceptance by human society of murderous food shortages, without efforts to remedy them, is a scandalous injustice and a grave offense. 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 (Amos 8:4-10).

Unintentional killing is not morally imputable (manslaughter that is truly unintentional and possibly unavoidable). But one is not exonerated from grave offense if, without proportionate reasons, he has acted in a way that brings about someone's death, even without the intention to do so.

Abortion
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.

Before I formed you in the womb I knew you, and before you were born I consecrated you (Jer 1:5; Job 10:8-12; Ps 22:10-11). My frame was not hidden from you, when I was being made in secret, intricately wrought in the depths of the earth (Ps 139:15).

Since the first century the Church has affirmed the moral evil of every intentional abortion. This teaching has not changed and remains unchangeable. Direct abortion, that is to say, abortion willed either as an end or a means, is contrary to the moral law: “You shall not kill the embryo by abortion and shall not cause the newborn to perish” (Didache 2, 2: SCh 248, 148; cf. Ep. Barnabae 19, 5: PG 2, 777; Ad Diognetum 5, 6: PG 2, 1173; Tertullian, Apol. 9: PL 1, 319-320).

Formal cooperation in an abortion constitutes a grave offense. The Church attaches the canonical penalty of excommunication to this crime against human life. In doing this, the Church does not thereby intend to restrict the scope of mercy. Rather, she makes clear the gravity of the crime committed, the irreparable harm done to the innocent who is put to death, as well as to the parents and the whole of society.

The inalienable right to life of every innocent human individual is a constitutive element of a civil society and its legislation. The moment a 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. 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.

It is immoral to produce human embryos intended for exploitation as disposable biological material. Certain attempts to influence chromosomic or genetic inheritance are not therapeutic but are aimed at producing human beings selected according to sex or other predetermined qualities. Such manipulations are contrary to the dignity of the human being who has been created in the image of God.

Euthanasia
Those whose lives are diminished or weakened deserve special respect. Sick or handicapped persons should be helped to lead lives as normal as possible. Whatever its motives and means, it is morally unacceptable to put an end to the lives of handicapped, sick, or dying persons.

Thus an act or omission which, of itself is intended to cause death in order to eliminate suffering constitutes a murder contrary to this commandment. The error of judgment into which one can fall in good faith does not change the nature of this murderous act, which must always be forbidden and excluded.

Discontinuing medical procedures that are burdensome, dangerous, extraordinary, or disproportionate to the expected outcome can be legitimate, in as much as 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. The decisions should be made by the patient if he is competent and able or, if not, by those legally entitled to act for the patient.

Even if death is thought imminent, the ordinary care owed to a sick person cannot be legitimately interrupted. The use of painkillers to alleviate the sufferings of the dying, even at the risk of shortening their days, can be morally in conformity with human dignity if death is not willed as either an end or a means, but only foreseen and tolerated as inevitable.

Suicide
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.

Suicide contradicts the majesty of being made in God’s image. It offends love of neighbor because it unjustly breaks the ties of solidarity with family, community, church, and other human societies to which we continue to have obligations. Suicide is contrary to love for the living God.

Voluntary co-operation in suicide is contrary to the moral law. However, grave psychological disturbances, anguish, or grave fear of hardship, suffering, or torture can diminish the responsibility of the one committing suicide.

II. Respect for the Dignity of Being Made in the Image of God
Respect for the souls of others: scandal

“Woe to the world because of its stumbling blocks! For it is inevitable that stumbling blocks come; but woe to that man through whom the stumbling block comes!” (Matt 18:7) “The wages of sin is death, but the gift of God is eternal life through Christ Jesus our Lord” (Rom 6:23).

Scandal is an attitude or behavior which leads another to do evil. The person who causes scandal becomes his neighbor's tempter. He damages virtue and integrity; he promotes the practice of sin; he may even draw his brother into spiritual death.

Scandal takes on a particular gravity by reason of the position of authority of those who cause it or the weakness of those who are scandalized. It prompted our Lord to utter this curse: "Whoever causes one of these little ones who believe in me to sin, it would be better for him to have a great millstone fastened round his neck and to be drowned in the depth of the sea" (Matt 18:6; 1 Cor 8:10-13). Scandal is grave when caused by those who by nature or office are obliged to teach and educate others. This is especially true when scandal takes place in the church. Peter addresses this in the second chapter of his second letter.

Scandal can be provoked by laws or institutions, by fashion or opinion. Therefore, they are guilty of scandal who establish laws or social structures leading to the decline of morals and the corruption of religious practice. This is true of business leaders who make rules encouraging fraud, parents and teachers who provoke their children to anger (Eph 6:4; Col. 3:21), or manipulators of public opinion who turn it away from moral values.

Therefore, anyone who uses the power at his disposal in such a way that it leads others to do wrong becomes guilty of scandal and responsible for the evil that he has directly or indirectly encouraged.

Respect for the human body
Life and physical health are precious gifts entrusted to us by God. We must take reasonable care of them, taking into account the needs of others and the common good.

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.

The use of drugs inflicts very grave damage on human health and life. Their use, except on strictly therapeutic grounds, is a grave offense. The production of and trafficking in illegal drugs are scandalous practices. They constitute direct co-operation in evil, since they encourage people to practices contrary to God’s law.

Science and technology are precious resources when placed at the service of man and promote his integral development for the benefit of all. However, it is an illusion to claim moral neutrality in scientific research and its applications. Therefore, science and technology by their very nature require unconditional respect for fundamental moral criteria. They must be at the service of the human person, of his inalienable rights, of his true and integral good, in conformity with the plan and the will of God.

Kidnapping and hostage taking bring on a reign of terror; by means of threats they subject their victims to intolerable pressures. They are morally wrong. Terrorism threatens, wounds, and kills indiscriminately; it is gravely against justice and love. Torture which uses physical or moral violence to extract confessions, punish the guilty, frighten opponents, or satisfy hatred is contrary to respect for the person and for human dignity. Except when performed for strictly therapeutic medical reasons, directly intended amputations, mutilations, and sterilizations performed on innocent persons are against the moral law.

In times past, cruel practices were commonly used by legitimate governments to maintain law and order, often without protest from the Pastors of the Church, who themselves adopted in their own tribunals the prescriptions of Roman law concerning torture. This is regrettable for these cruel practices are against the ways of God, deny brotherly love, devalue the sanctity of life, and are not necessary for public order. On the contrary, these practices lead to ones even more degrading. It is necessary to pray and work for their abolition.

III. Safeguarding Peace
By recalling the commandment, "You shall not kill" (Matt 5:21), our Lord asked for peace of heart and denounced murderous anger and hatred as immoral. Anger is a desire for revenge. It is right for the safety of the community to impose discipline, punishment, and restitution to stop evil and maintain justice. However, when anger reaches the point of a deliberate desire to kill or seriously wound a neighbor, it is gravely against God and love; it is a mortal sin. The Lord says, "Everyone who is angry with his brother shall be liable to judgment" (Matt 5:22).

Deliberate hatred is rebellion against God and contrary to love. Hatred of the neighbor is a sin when one deliberately wishes him evil, or when one deliberately desires him harm. Jesus said to “Love your enemies and pray for those who persecute you, so that you may be sons of your Father who is in heaven” (Matt 5:44-45).

Respect for and development of human life requires peace. Peace is not merely the absence of war, and it is not limited to maintaining a balance of powers between adversaries. Peace is "the tranquillity of order" (St. Augustine). Peace is the work of justice and the effect of brotherly love (Isa 32:17). Earthly peace is the image and fruit of the messianic "Prince of Peace." By the blood of his Cross, Christ reconciled men with God and made his Church the primary example of the unity of the human race and of its union with God.

Avoiding war
The fifth commandment forbids the intentional destruction of human life. Because of the evils and injustices that accompany all war, the Church urges everyone to prayer and to action so that the divine Goodness may free us from the age old bondage of war. All citizens, and especially Christian citizens, and all governments are obliged to work for the avoidance of war. However, as long as the danger of war persists and there is no international authority with the necessary competence and power, governments cannot be denied the right of lawful self-defense, once all peace efforts have failed. And yet, the use of arms must not produce evils and disorders graver than the evil to be eliminated. the power of modem means of destruction weighs very heavily in evaluating this condition.

God’s word and the Church both assert the permanent validity of the moral law during armed conflict. The fact that war has broken out does not mean that everything becomes legal or justifiable between the warring parties. Non-combatants, wounded soldiers, and prisoners must be respected and treated humanely. Actions deliberately contrary to the laws of God and to God’s universal principle of loving your neighbor as yourself, are crimes, as are the orders that command such actions. Blind obedience does not suffice to excuse those who carry them out. Thus the extermination of a people, nation, or ethnic minority is murder. One is morally bound to resist orders that command genocide.

A danger of modern warfare is that it provides the opportunity to those who possess modern weapons – especially atomic, biological, or chemical weapons – to commit the crime of the indiscriminate destruction of large areas of population.

Injustice, excessive economic or social inequalities, envy, distrust, and pride raging among men and nations constantly threaten peace and cause wars. The Church and individual Christians ought to do everything possible to overcome these disorders through evangelism, public teaching, and growing to spiritual maturity so as to contributes to building up peace and avoiding war.

"Blessed are the peacemakers, for they shall be called sons of God" (Mt 5:9).