Thomas Aquinas, Compendium of Theology

Thus there is no reason why God should not have knowledge of individual effects, or why He should not directly regulate them by Himself, even though He may carry them out through intermediate causes. However, in the very execution He is, in some fashion, in immediate touch with all effects, to the extent that all intermediate causes operate in virtue of the first cause, so that in a certain way He Himself appears to act in them all. Thus all the achievements of secondary causes can be attributed to Him, as the effect produced by a tool is ascribed to the artisan; when we say that a smith makes a knife, we are more correct than when we say that a hammer did it. God is also in immediate contact with all effects so far as He is per se the cause of their existence, and so far as everything is kept in being by Him.

Corresponding to these three immediate modes of influence, God is said to be in everything by essence, power, and presence. He is in everything by His essence inasmuch as the existence of each thing is a certain participation in the divine essence; the divine essence is present to every existing thing, to the extent that it has existence, as a cause is present to its proper effect. God is in all things by His power, inasmuch as all things operate in virtue of Him. And God is in all things by His presence, inasmuch as He directly regulates and disposes all things.