(CG 3/67). That God is the Cause of Activity in all Active Agents (Book 3. God, the End of Creatures) (Summa Contra Gentiles) (Aquinas, Thomas, St.)

AN incorporeal thing is said to be in a thing by contact of power. Therefore if there be anything incorporeal fraught with infinite power, that must be everywhere. But it has been shown (B. I Chap. XLIII) that God has infinite power. He is therefore everywhere.

4. Since God is the universal cause of all being, in whatever region being can be found there must be the divine presence.

6. An efficient cause must be together with its proximate and immediate effect. But in everything there is some effect which must be set down for the proximate and immediate effect of God's power: for God alone can create (B. II, Chap. XXI); and in everything there is something caused by creation,�in corporeal things, primordial matter; in incorporeal beings, their simple essences (B. II, Chapp. XV, sq). God then must be in all things, especially since the things which He has once produced from not-being to being He continually and always preserves in being (Chap. LXV).

Hence it is said: I fill heaven and earth (Jer. xxiii, 24): If I ascend into heaven, you are there: if I descend into hell, you are there (Ps. cxxxviii, 8).

God is indivisible, and wholly out of the category of the continuous: hence He is not determined to one place, great or small, by the necessity of His essence, seeing that He is from eternity before all place: but by the immensity of His power He reaches all things that are in place, since He is the universal cause of being. Thus then He is whole everywhere, reaching all things by His undivided power.