The Catechism teaches that the fifth commandment forbids the intentional destruction of human life and urges everyone to prayer and action so that God may free us from the bondage of war (CCC 2307). Governments may exercise lawful self-defense only after peace efforts have failed and only under strict moral conditions, including grave and certain harm, the exhaustion of other means, serious prospects of success, and avoidance of evils worse than the one being addressed (CCC 2308-2309). Public authorities may require what is necessary for national defense, while also making equitable provision for those who refuse to bear arms for reasons of conscience and who must serve the human community in another way (CCC 2310-2311). The Church affirms that the moral law remains in force during armed conflict: non-combatants, wounded soldiers, and prisoners must be treated humanely, and genocide and indiscriminate destruction of cities or populations are gravely condemned (CCC 2312-2314). The Catechism also warns that the arms race does not ensure peace and can aggravate conflict, hinder aid to needy populations, and increase the danger of escalation; the production and sale of arms must therefore be regulated for the common good (CCC 2315-2316). For Catholic families, these passages invite us to pray for peace and to recognize that overcoming injustice, distrust, envy, and pride helps build peace and avoid war (CCC 2307, 2317).
The Catechism teaches that every human life is sacred from conception until death, because each person is willed for his or her own sake in the image and likeness of the living and holy God. Murder is gravely contrary to personal dignity and the holiness of the Creator; direct abortion is gravely contrary to the moral law; intentional euthanasia is gravely contrary to personal dignity and respect due to God; and suicide is seriously contrary to justice, hope, and charity and is forbidden by the fifth commandment. From conception, the child has the right to life; because the embryo must be treated as a person, it must be defended in its integrity, cared for, and healed like every other human being. Legitimate defense may be necessary to stop an unjust aggressor from causing harm, especially when others’ lives or the common good are entrusted to our care. As we pray and reflect together, we are also called to seek peace: to do all reasonably possible to avoid war, reject crimes in armed conflict, and remember Christ’s blessing on the peacemakers.