Catechism: The Fifth Commandment
CCC 2259: The Fifth Commandment ➔
In Catholic teaching, the Fifth Commandment “You shall not kill” goes far beyond simply prohibiting murder. It’s a profound affirmation of the value of human life, rooted in the belief that life is a sacred gift from God. As such it is precious from the moment of conception to natural death. God alone is the Lord of life, and no one may directly destroy an innocent human being. The commandment also forbids murderous anger, hatred, and vengeance, as Jesus indicated in his Sermon on the Mount. Remember how Jesus said in Mt 5:21-22, “You have heard that people were told in the past, ‘Do not commit murder; anyone who does will be brought to trial.’ But now I tell you: whoever is angry with his brother will be brought to trial, whoever calls his brother ‘You good-for-nothing!’ will be brought before the Council, and whoever calls his brother a worthless fool will be in danger of going to the fire of hell.”
The fifth commandment prohibits intentional homicide, including murder, abortion, euthanasia, and suicide. It also rules out indirect killing, such as exposing someone to mortal danger without grave reason, e.g., King David putting Uriah the Hittite, the husband of Bathsheba, in the frontline of the army so that he would be killed.
The fifth commandment does not forbid legitimate self-defence, when proportionate and necessary, e.g., if you or an innocent person, such as a child, is being attacked by an unjust aggressor. In certain circumstances this principle allows for a just war. To morally justify going to war, all of the following must be met:
Grave and lasting damage: The aggressor must inflict serious harm that is
certain.
Last resort: All peaceful alternatives must have been tried and failed.
Serious prospects of success: The war must have a reasonable chance of
achieving its goals.
Proportionality. Even a defensive response to an unjust attack may go far
beyond legitimate defense if it causes destruction that violates the principle of
proportionality, e.g., the Israeli response to the Hamas attack seems to lack
proportionality.
There was an interesting discussion about this topic in the GPO in 1916. According to Thomas Coffee’s book, Agony at Easter: The 1916 Irish Uprising the rebel leaders discussed the topic. Former taoiseach John Bruton argued on many occasions, that the violence of the Rising and the War of Independence was not necessary to achieve Irish independence. There was a non-violent alternative, and thousands of lives would have been saved by sticking to constitutional politics. I share Bruton’s belief. In conflict situations the Church encourages forgiveness and reconciliation, even with enemies.
Speaking about capital punishment the American bishops echo Catholic teaching when they say in A Culture of Life and the Penalty of Death, “In Catholic teaching the state has t impose the death penalty upon criminals convicted of heinous crimes if this ultimate sanction is the only available means to protect society from a grave threat to human life. However, this right should not be exercised when other ways are available to punish criminals and to protect society that are more respectful of human life.” Capital punishment in Ireland was abolished in statute law in 1990, having been abolished in 1964 for most offences including ordinary murder.
Implicit in respect for life is a concern to promote health and dignity, including access to basic needs like food, shelter, and medical care. It also involves compassion for the vulnerable, especially the unborn, the sick, and the dying. The Catholic Church sees this commandment as a call to protect life in all its forms, not just avoid the taking of life. It’s a moral compass that touches everything from bioethics to social justice. That said, Pope St John Paul II said on a number of occasions that we are living in a culture of death. He warned that this culture “ends up becoming the freedom of ‘the strong’ against the weak who have no choice but to submit” (The Gospel of Life, 19).