Pacem in Terris §38

³⁸ But such an order—universal, absolute and immutable in its principles—finds its source in the true, personal and transcendent God. He is the first truth, the sovereign good, and as such the deepest source from which human society, if it is to be properly constituted, creative, and worthy of man's dignity, draws its genuine vitality. (26) This is what St. Thomas means when he says: "Human reason is the standard which measures the degree of goodness of the human will, and as such it derives from the eternal law, which is divine reason . . . Hence it is clear that the goodness of the human will depends much more on the eternal law than on human reason." (27)