Whosoever shall kill Qayin, shall be punished sevenfold. And the Lord set a mark upon Qayin, so that whoever found him should not kill him (Gn 4:15).
Pope Francis, elaborating the teachings of the Catholic Church on capital punishment and developing the teachings of Saint John Paul II and Pope Emeritus Benedict XVI on the issue, has at last declared openly that “The Church teaches, in the light of the Gospel, that the death penalty is inadmissible because it is an attack on the inviolability and dignity of the person.” He has also instructed that the Catechism of the Catholic Church be accordingly updated (§2267).
To understand more about this long-due elaboration of the Faith and its grounded hermeneutic of continuity with previous teachings, you can read more at Is the Death Penalty Just? This addresses the issue of capital punishment from Blessed Paul XVI through the teachings of the Church up to the end of 2017.
The declaration of Pope Francis is of particular importance and implication in this day and age, given the barbaric nature of capital punishment that is still meted out without hesitation (if not with actual sadistic glee) in the United States – a punishment cheered-for by many American Catholics and White Evangelicals alike “in the Name of God” – because the US is still supposed to be the most ‘civilized’ country in the world.