From Pope St. John Paul II’s encyclical Veritatis Splendor (1993):
The Second Vatican Council points out that the “supreme rule of life is the divine law itself, the eternal, objective and universal law by which God out of his wisdom and love arranges, directs and governs the whole world and the paths of the human community. God has enabled man to share in this divine law, and hence man is able under the gentle guidance of God’s providence increasingly to recognize the unchanging truth”.78
The Council refers back to the classic teaching on God’s eternal law. Saint Augustine defines this as “the reason or the will of God, who commands us to respect the natural order and forbids us to disturb it”.79 Saint Thomas identifies it with “the type of the divine wisdom as moving all things to their due end”.80 And God’s wisdom is providence, a love which cares. God himself loves and cares, in the most literal and basic sense, for all creation (cf. Wis 7:22; 8:11). But God provides for man differently from the way in which he provides for beings which are not persons. He cares for man not “from without”, through the laws of physical nature, but “from within”, through reason, which, by its natural knowledge of God’s eternal law, is consequently able to show man the right direction to take in his free actions.81 In this way God calls man to participate in his own providence, since he desires to guide the world — not only the world of nature but also the world of human persons — through man himself, through man’s reasonable and responsible care. The natural law enters here as the human expression of God’s eternal law. Saint Thomas writes: “Among all others, the rational creature is subject to divine providence in the most excellent way, insofar as it partakes of a share of providence, being provident both for itself and for others. Thus it has a share of the Eternal Reason, whereby it has a natural inclination to its proper act and end. This participation of the eternal law in the rational creature is called natural law”.82
78 Declaration on Religious Freedom Dignitatis Humanæ, 3.
79 Contra Faustum, Bk 22, Chap. 27: Patrologiæ Cursus completus, Series Latina 42, 418.
80 Summa Theologiæ, I-II, q. 93, a. 1.
81 Cf. ibid., I-II, q. 90, a.4, ad 1um.
82 Ibid., I-II, q. 91, a.2.
— Veritatis Splendor 43