From Pope St. John Paul II’s encyclical Veritatis Splendor (1993):
The Christian, thanks to God’s Revelation and to faith, is aware of the “newness” which characterizes the morality of his actions: these actions are called to show either consistency or inconsistency with that dignity and vocation which have been bestowed on him by grace. In Jesus Christ and in his Spirit, the Christian is a “new creation”, a child of God; by his actions he shows his likeness or unlikeness to the image of the Son who is the first-born among many brethren (cf. Rom 8:29), he lives out his fidelity or infidelity to the gift of the Spirit, and he opens or closes himself to eternal life, to the communion of vision, love and happiness with God the Father, Son and Holy Spirit.123 As Saint Cyril of Alexandria writes, Christ “forms us according to his image, in such a way that the traits of his divine nature shine forth in us through sanctification and justice and the life which is good and in conformity with virtue . . . The beauty of this image shines forth in us who are in Christ, when we show ourselves to be good in our works”.124
Consequently the moral life has an essential “teleological” character, since it consists in the deliberate ordering of human acts to God, the supreme good and ultimate end (telos) of man. This is attested to once more by the question posed by the young man to Jesus: “What good must I do to have eternal life?”. But this ordering to one’s ultimate end is not something subjective, dependent solely upon one’s intention. It presupposes that such acts are in themselves capable of being ordered to this end, insofar as they are in conformity with the authentic moral good of man, safeguarded by the commandments. This is what Jesus himself points out in his reply to the young man: “If you wish to enter into life, keep the commandments” (Mt 19:17).
Clearly such an ordering must be rational and free, conscious and deliberate, by virtue of which man is “responsible” for his actions and subject to the judgment of God, the just and good judge who, as the Apostle Paul reminds us, rewards good and punishes evil: “We must all appear before the judgment seat of Christ, so that each one may receive good or evil, according to what he has done in the body” (2 Cor 5:10).
123 The Second Vatican Council, in the Pastoral Constitution on the Church in the Modern World, makes this clear: “This applies not only to Christians but to all men of good will in whose hearts grace is secretly at work. Since Christ died for all and since man’s ultimate calling comes from God and is therefore a universal one, we are obliged to hold that the Holy Spirit offers to all the possibility of sharing in this paschal mystery in a manner known to God”: Gaudium et Spes, 22.
124 Tractatus ad Tiberium Diaconum sociosque, II. Responsiones ad Tiberium Diaconum sociosque: Saint Cyril of Alexandria, In Divi Johannis Evangelium, vol. III, ed. Philip Edward Pusey, Brussels, Culture et Civilisation (1965), 590.
— Veritatis Splendor 73