This distinction between the dictate (or exigency) of nature, and the divine law, answering to what Cardinal Newman calls " the critical and the judicial function of conscience" (Grammar of Assent pp. 102-107), is of the first importance in the theory of morals. I have endeavoured to bring it out elsewhere: Ethics and Natural Law, pp. 109-125. St Thomas speaks of the 'divine law' as known in the Jewish and Christian revelation. In a 'state of pure nature,' without revelation, we should have had to argue a priori that God must have willed to ratify the exigences of human nature and natural reason, and command their observance. What those exigences of nature are see Chap. CXXIX.
Of God and His Creatures: 3.123