Fides et Ratio §68

⁶⁸ Moral theology has perhaps an even greater need of philosophy's contribution. In the New Testament, human life is much less governed by prescriptions than in the Old Testament. Life in the Spirit leads believers to a freedom and responsibility which surpass the Law. Yet the Gospel and the Apostolic writings still set forth both general principles of Christian conduct and specific teachings and precepts. In order to apply these to the particular circumstances of individual and communal life, Christians must be able fully to engage their conscience and the power of their reason. In other words, moral theology requires a sound philosophical vision of human nature and society, as well as of the general principles of ethical decision-making.