We have now to consider the extrinsic principles of acts. Now theextrinsic principle inclining to evil is the devil, of whosetemptations we have spoken in the First Part (Q. 114). But theextrinsic principle moving to good is God, Who both instructs us bymeans of His Law, and assists us by His Grace: wherefore in the firstplace we must speak of law; in the second place, of grace.
Concerning law, we must consider: (1) Law itself in general; (2) itsparts. Concerning law in general three points offer themselves forour consideration: (1) Its essence; (2) The different kinds of law;(3) The effects of law.
Under the first head there are four points of inquiry:
(1) Whether law is something pertaining to reason?
(2) Concerning the end of law;
(3) Its cause;
(4) The promulgation of law.
Whether Law Is Something Pertaining to Reason?