Summa contra Gentiles3.89 Chapter LXXXIX. That the movement of the will, and not only the power of the will, is caused by God

Some, nevertheless, unable to understand how God can cause in us the movement of the will without prejudice to liberty, have endeavoured to give a false exposition to the authorities quoted. They say, in fact, that God causes in us to will and to accomplish, by causing in us the power to will, and not by causing us to will this or that. This is the exposition of Origen (3 Peri Arch, i.) who defended free-will in a sense contrary to the aforesaid authorities.

Apparently this was the source of the opinion of some who maintained that providence does not regard things subject to free-will, namely our elections, but only external happenings. For he who chooses to get or do something, for instance to build or get rich, is not always able to succeed; and so the outcome of our actions is not subject to our free-will, but is ordained by providence.

But the authority of Scripture is in manifest opposition to all this: for it is said (Isa. xxvi. 12): 0 Lord, Thou hast wrought all our works in us. Hence we receive from God not only the power to will, but also our very operations.

Further. The very words of Solomon, Whithersoever He will He shall turn it, show that the divine causality extends not only to the will, but also to its act.

Again. Not only does God give things their powers, but also nothing can act by its own power, unless it act by His power, as we proved above. Therefore man cannot use the will-power given to him, except forasmuch as he acts by God's power. Now the thing by whose power the agent acts, is the cause not only of the power but also of the act. This is apparent in the craftsman, by whose power the instrument acts, even though it may not have received its form from the craftsman in question, and is merely applied by him to action. Therefore God is the cause not only of our will but also of our willing.

Further. Order in spiritual things is more perfect than in corporeal things. Now in corporeal things every movement is caused by the first movement. Therefore in spiritual things every movement of the will must be caused by the first will, which is God’s.

Besides. We proved above that God is the cause of every action, and that He works in every agent. Therefore He is the cause of the movements of the will.

Again. Aristotle argues in the same sense (8 Ethic. Eudem.) as follows. There must be some cause of a person understanding, taking counsel, choosing and willing, because everything new must have a cause. And if the cause of these acts was another act of counsel and another act of will, since in such things we cannot proceed to infinity, we must come at length to something first. And this first thing must be something better than the reason. And nothing but God is better than the intellect and the reason. Therefore God is the first principle of our counsels and wills.