5 But the world's Creator has stamped man's inmost being with an order revealed to man by his conscience; and his conscience insists on his preserving it. Men "show the work of the law written in their hearts. Their conscience bears witness to them." (5) And how could it be otherwise? All created being reflects the infinite wisdom of God. It reflects it all the more clearly, the higher it stands in the scale of perfection. (6)
Source: Pacem in Terris (Vatican.va)