Chapter 99 — That God’s life is eternal

It follows from this that God’s life is eternal.

For nothing ceases to live except by being severed from life. But nothing can be severed from itself: for all severance results from the separation of one thing from another. Therefore, it is impossible that God cease to live, since himself is his own life, as we have proved. (Ch. 98.)

Again. Whatever sometimes is and sometimes is not results from a cause: for nothing brings itself from non-being to being, since what does not yet exist does not act. Now the divine life has no cause, as neither has the divine existence. Therefore, he is not sometimes living and sometimes not living, but is ever living. Therefore, his life is eternal.

Again. In every operation the operator remains, although sometimes the operation is transitory by way of succession: thus in movement, the thing moved remains the same identically though not logically. Hence where action is the agent itself, it follows that nothing passes by in succession, but that the whole is simultaneously the same throughout. Now in God to understand and to live are God himself, as was proved. (Cc. 45, 98.) Therefore, his life is without succession and is simultaneously whole. (ST I.10.1.) Therefore, it is eternal.

Moreover. God is utterly unchangeable, as we have proved above. (Ch. 13.) But that which begins or ceases to live, or is subject to succession in living, is changeable: for the life of a being begins by generation and ceases by corruption, and succession results from change of some kind. Therefore, God neither began to be, nor will cease to be, nor is subject to succession in living. Therefore, his life is eternal.

Therefore, it is said in the person of the Lord: I live forever (Deut 32:40); and: this is the true God and eternal life (1 John 5:20).