Summa contra Gentiles1.97 Chapter XCVII. That God is a living being

From what has been already proved, it follows of necessity that God is a living being.

For it has been shown that in God there are intelligence and will. Now intelligence and will are only in that which lives. Therefore God is a living being.

Again. Life is ascribed to certain things in as much as they seem to be set in motion of themselves and not by another. For which reason, things which seem to be moved of themselves, the cause of which movement is not perceived by the unlearned, are described metaphorically as living: for instance we speak of the living water of aflowing source, but not of a tank or stagnant pond; and of ' quick '-silver, which seems to have a kind of movement. For properly speaking those things alone are themselves in motion, which move themselves, being composed of mover and moved, such as animate beings. Wherefore such things alone are said to live, while all others are moved by some other thing, either as generating them, or as removing an obstacle, or as impelling them. And since sensible operations are accompanied by movement, furthermore whatever moves itself to its proper operations, although these be without movement, is said to live: wherefore intelligence, appetite and sensation are vital actions. Now God especially works not as moved by another but by Himself, since He is the first active cause. Therefore to live is befitting Him above all.

Again. The divine being contains every perfection of being, as was shown above. Now life is a kind of perfect existence; wherefore living beings are placed above not-living things in the order of beings. Therefore God's being is life. Therefore He is a living being.

This is confirmed by the authority of divine Scripture. For it is said (Deut. xxxii. 40) in the person of the Lord: J will say: I live for ever, and in the psalm My heart and my flesh have rejoiced in the living God.