From Pope St. John Paul II’s encyclical Veritatis Splendor (1993):
We do not know how clearly the young man in the Gospel understood the profound and challenging import of Jesus’ first reply: “If you wish to enter into life, keep the commandments”. But it is certain that the young man’s commitment to respect all the moral demands of the commandments represents the absolutely essential ground in which the desire for perfection can take root and mature, the desire, that is, for the meaning of the commandments to be completely fulfilled in following Christ. Jesus’ conversation with the young man helps us to grasp the conditions for the moral growth of man, who has been called to perfection: the young man, having observed all the commandments, shows that he is incapable of taking the next step by himself alone. To do so requires mature human freedom (“If you wish to be perfect”) and God’s gift of grace (“Come, follow me”).
Perfection demands that maturity in self-giving to which human freedom is called. Jesus points out to the young man that the commandments are the first and indispensable condition for having eternal life; on the other hand, for the young man to give up all he possesses and to follow the Lord is presented as an invitation: “If you wish . . .”. These words of Jesus reveal the particular dynamic of freedom’s growth towards maturity, and at the same time they bear witness to the fundamental relationship between freedom and divine law. Human freedom and God’s law are not in opposition; on the contrary, they appeal one to the other. The follower of Christ knows that his vocation is to freedom. “You were called to freedom, brethren” (Gal 5:13), proclaims the Apostle Paul with joy and pride. But he immediately adds: “only do not use your freedom as an opportunity for the flesh, but through love be servants of one another” (ibid.). The firmness with which the Apostle opposes those who believe that they are justified by the Law has nothing to do with man’s “liberation” from precepts. On the contrary, the latter are at the service of the practice of love: “For he who loves his neighbour has fulfilled the Law. The commandments, ‘You shall not commit adultery; You shall not murder; You shall not steal; You shall not covet,’ and any other commandment, are summed up in this sentence, ‘You shall love your neighbour as yourself'” (Rom 13:8-9). Saint Augustine, after speaking of the observance of the commandments as being a kind of incipient, imperfect freedom, goes on to say: “Why, someone will ask, is it not yet perfect? Because ‘I see in my members another law at war with the law of my reason’ . . . In part freedom, in part slavery: not yet complete freedom, not yet pure, not yet whole, because we are not yet in eternity. In part we retain our weakness and in part we have attained freedom. All our sins were destroyed in Baptism, but does it follow that no weakness remained after iniquity was destroyed? Had none remained, we would live without sin in this life. But who would dare to say this except someone who is proud, someone unworthy of the mercy of our deliverer? . . . Therefore, since some weakness has remained in us, I dare to say that to the extent to which we serve God we are free, while to the extent that we follow the law of sin, we are still slaves”.27
27 In Iohannis Evangelium Tractatus, 41, 10: Corpus Christianorum, Latin series 36, 363.
— Veritatis Splendor 17