"Who showeth us good things? The light of Thy countenance, O Lord, is signed upon us: Thou hast given gladness in my heart" (Ps. iv. 6, 7). The Eternal Law which exists in God is in the first instance promulgated to men, not by outward revelation and the imposing of formal statutes, but inwardly in their consciousness. Every rational creature has a certain light from God that is totally deficient in the lower animals, a certain apprehension of good and evil in the intellect, and a certain impulsion towards moral goodness and aversion from evil. This apprehension is spontaneous, and is antecedent to the knowledge that comes from special revelation, or instruction, or human law and custom, although concurrent with them. It comes to us in the course of nature; its object is to guide us in our natural course, so that we may lead a higher life than the animals, who are guided solely by sense; it is therefore known as the natural moral law. Conscience is clearly allied with the natural law; it takes cognizance, however, of more than the natural law; it forms its conclusions from every form of divine law that is manifested to it, and it reduces this law to practice, and makes the application of it to particular cases as they arise. St. Paul describes the universality of the natural law. "The Gentiles, who have not the law, do by nature those things which are of the law . . . who show the work of the law written in their hearts, their conscience bearing witness to them, and their thoughts within themselves accusing them or else defending them" (Rom. ii. 14, 15). Thank the good Providence of God for thus making spiritual provision for all mankind.
