Evangelium Vitae §40

⁴⁰ The sacredness of life gives rise to its inviolability, written from the beginning in man's heart, in his conscience. The question: "What have you done?" (Gen 4:10), which God addresses to Cain after he has killed his brother Abel, interprets the experience of every person: in the depths of his conscience, man is always reminded of the inviolability of life-his own life and that of others-as something which does not belong to him, because it is the property and gift of God the Creator and Father. The commandment regarding the inviolability of human life reverberates at the heart of the "ten words" in the covenant of Sinai (cf. Ex 34:28). In the first place that commandment prohibits murder: "You shall not kill" (Ex 20:13); "do not slay the innocent and righteous" (Ex 23:7). But, as is brought out in Israel's later legislation, it also prohibits all personal injury inflicted on another (cf. Ex 21:12-27). Of course we must recognize that in the Old Testament this sense of the value of life, though already quite marked, does not yet reach the refinement found in the Sermon on the Mount. This is apparent in some aspects of the current penal legislation, which provided for severe forms of corporal punishment and even the death penalty. But the overall message, which the New Testament will bring to perfection, is a forceful appeal for respect for the inviolability of physical life and the integrity of the person. It culminates in the positive commandment which obliges us to be responsible for our neighbour as for ourselves: "You shall love your neighbour as yourself" (Lev 19:18).