From Pope St. John Paul II’s encyclical Veritatis Splendor (1993):
Jesus’ answer [to the question “Teacher, what good must I do to have eternal life?”] is not enough for the young man, who continues by asking the Teacher about the commandments which must be kept: “He said to him, ‘Which ones?’ ” (Mt 19:18). He asks what he must do in life in order to show that he acknowledges God’s holiness. After directing the young man’s gaze towards God, Jesus reminds him of the commandments of the Decalogue regarding one’s neighbour: “Jesus said: ‘You shall not murder; You shall not commit adultery; You shall not bear false witness; Honour your father and mother; also, You shall love your neighbour as yourself'” (Mt 19:18-19).
From the context of the conversation, and especially from a comparison of Matthew’s text with the parallel passages in Mark and Luke, it is clear that Jesus does not intend to list each and every one of the commandments required in order to “enter into life”, but rather wishes to draw the young man’s attention to the “centrality” of the Decalogue with regard to every other precept, inasmuch as it is the interpretation of what the words “I am the Lord your God” mean for man. Nevertheless we cannot fail to notice which commandments of the Law the Lord recalls to the young man. They are some of the commandments belonging to the so-called “second tablet” of the Decalogue, the summary (cf. Rom 13:8-10) and foundation of which is the commandment of love of neighbour: “You shall love your neighbour as yourself” (Mt 19:19; cf. Mk 12:31). In this commandment we find a precise expression of the singular dignity of the human person, “the only creature that God has wanted for its own sake”.21 The different commandments of the Decalogue are really only so many reflections of the one commandment about the good of the person, at the level of the many different goods which characterize his identity as a spiritual and bodily being in relationship with God, with his neighbour and with the material world. As we read in the Catechism of the Catholic Church, “the Ten Commandments are part of God’s Revelation. At the same time, they teach us man’s true humanity. They shed light on the essential duties, and so indirectly on the fundamental rights, inherent in the nature of the human person”.22
The commandments of which Jesus reminds the young man are meant to safeguard the good of the person, the image of God, by protecting his goods. “You shall not murder; You shall not commit adultery; You shall not steal; You shall not bear false witness” are moral rules formulated in terms of prohibitions. These negative precepts express with particular force the ever urgent need to protect human life, the communion of persons in marriage, private property, truthfulness and people’s good name.
The commandments thus represent the basic condition for love of neighbour; at the same time they are the proof of that love. They are the first necessary step on the journey towards freedom, its starting-point. “The beginning of freedom”, Saint Augustine writes, “is to be free from crimes . . . such as murder, adultery, fornication, theft, fraud, sacrilege and so forth. When once one is without these crimes (and every Christian should be without them), one begins to lift up one’s head towards freedom. But this is only the beginning of freedom, not perfect freedom . . .”.23
21 Second Vatican Ecumenical Council, Pastoral Constitution on the Church in the Modern World Gaudium et Spes, 24.
22 Catechism of the Catholic Church, No. 2070.
23 In Iohannis Evangelium Tractatus, 41, 10: Corpus Christianorum, Latin series, 36, 363.
— Veritatis Splendor 13