Of the Greeks, some have said that God is the soul of the world; others that his power does not extend to earth but only to heaven. Some, laboring under a similar delusion, misinterpret the text "and your faithfulness to the skies" and have dared to limit the providence of God to the skies and heaven and to alienate from God the things on earth, forgetting the psalm that says, "If I go up to the heavens, you are there; if I sink to the underworld, you are present there." For if there is nothing higher than heaven and the underworld is deeper than the earth, he who rules the lower regions reaches the earth also.
Source: Catechetical Lecture 8:2