Chapter 67 — That in all things that operate God is the cause of their operating

Hence it is clear that in all things that operate God is the cause of their operating. For everyone that operates is in some way a cause of being, either of essential or of accidental being. But nothing is a cause of being except insofar as it acts by God’s power. Therefore, everyone that operates acts by God’s power.

Again. Every operation consequent to a certain power is ascribed to the giver of that power as effect to cause. Thus the natural movement of heavy and light bodies is consequent to their form, whereby they are heavy or light—hence the cause of their movement is said to be that which produced them and gave them their form. Now all power of any agent whatsoever is from God, as from the first principle of all perfection. Therefore, since all operation is consequent to some power, it follows that God is the cause of every operation.

Moreover. It is clear that every action that cannot continue after the influence of a certain agent has ceased is from that agent: thus the visibility of colors cannot continue after the action of the sun has ceased to enlighten the air, and therefore without doubt it is the cause of the visibility of colors. The same applies to violent motion, which ceases when the violence of the impelling force has ceased. Now, since God not only gave existence to things when they first began to exist, but also causes existence in them as long as they exist by preserving them in existence, as we have proved, (Ch. 65.) so not only did he give them active forces when he first made them, but is always causing those forces in them. Consequently, if the divine influence were to cease, all operation would come to an end. Therefore, every operation of a thing is reducible to him as its cause.

Besides. Whatever applies an active power to action is said to be the cause of that action. For the craftsman, when he applies the forces of nature to an action, is said to be the cause of that action, as the cook is the cause of cooking, which is done by fire. Now every application of power to action is chiefly and primarily from God. For active forces are applied to their proper operations by some movement of the body or of the soul. Now the first principle of either movement is God. For he is the first mover, wholly immovable, as we have proved above. (Bk. 1, ch. 13.) Likewise, every movement of the will whereby certain powers are applied to action is reducible to God as the first object of appetite, and the first willer. Therefore, every operation should be ascribed to God as its first and principal agent.

Further. In all ordered active causes, the causes that follow must always act by the power of the first: thus in natural things the lower bodies act by the power of the heavenly bodies, and in voluntary things all the inferior craftsmen act in accordance with the direction of the master craftsman. Now, in the order of active causes, God is the first cause, as we proved in the first book. (Bk. 1, ch. 13.) Consequently, all the lower active causes act by his power. Now the cause of an action is the thing by whose power it is done, more even than that which does it: just as the principal agent is more the cause than the instrument. Therefore, God is more the cause of every action than even secondary active causes.

Further. Every operator is directed through its operation to its ultimate end, since its last end is either the operation itself or the thing operated (namely, the effect of the operation). Now it belongs to God himself to direct things to their end, as we have proved. (Ch. 64.) Therefore, we must conclude that every agent acts by the power of God: consequently, it is he who causes the actions of all things.

Hence it is said: You have wrought in us all our works (Isa 26:12); and: Apart from me you can do nothing (John 15:5); and: God is at work in us (Vulgate: you.) both to will and to work for his good pleasure (Phil 2:13). For this reason Sacred Scripture often ascribes natural effects to the divine operation, because it is he who works in every agent, natural or voluntary, as it is written in Job: Did you not pour me out like milk and curdle me like cheese? You did clothe me with skin and flesh, and knit me together with bones and sinews (Job 10:10–11); and again in the Psalm: The Lord thundered in the heavens, and the Most High uttered his voice, hailstones and coals of fire (Ps 18:13[17:14]).