Summa summae S. Thomae sive compendium theologiae

D. Thomas, q. 9.

[You will ask 1° whether God is altogether immutable.

I answer affirmatively¹.

This is against the Stoics, who, on the testimony of Origen, book III contra Celsum, held that God is a mutable body; and against the Socinians, who taught that God is mutable, not indeed in his substance, but in his decrees.

Proof 1°. This is of faith. The Council of Nicaea I: «Those who say that the Son of God is either created or mutable, the catholic and apostolic Church anathematizes.» In the Council of Lateran IV it was defined that God is immutable.

Proof 2°, from Scripture. Num., XXIII, 19: God is not as a man, that he should lie, nor as the son of man, that he should be changed. Malach., III, 6: I am the Lord, and I change not. James, I, 17: With whom there is no change, nor shadow of alteration.

Proof 3°, from reason², which is virtually threefold. For the nature of change there is required: 1° potentiality together with privation, as the term from which; 2° a form newly to be acquired, as the term to which; 3° a subject receptive, in succession, of several forms. But the first is excluded in God by reason of pure act, the second by reason of infinite perfection, the third by reason of supreme simplicity. Therefore.

It is confirmed. If God could be changed, he would be changed either for the better, or for the worse, or into something equal; or he would lose what he has, or acquire what he does not have. But it is manifest that all these imply imperfection.

You will say: God has become, and daily becomes, operative from non-operative, as is clear in the creation of the world, which took place in time, and is continued in the daily production of new effects. Therefore he is changed.

I answer, I deny the antecedent. For God from eternity effects what comes to be in time, because his operation, formally immanent and virtually transient, is not distinct from himself; for it is nothing other than his very will, by which he wills from eternity that something come to be in time; whence the whole change lies on the side of the creature. He is not, however, denominated from eternity as creating or operating, because the extrinsic denomination of creator or operator depends on the effect produced in time.

This difficulty St. Augustine excellently dispels, book XII de Civitate Dei, ch. 17, n. 2: «Because, he says, whatever new thing occurs to them [the gentile philosophers] as needing to be done, they do by a new plan, since indeed they bear mutable minds; assuredly, thinking not of God — whom they cannot conceive — but of themselves in his place, they compare not him, but themselves; not to him, but to themselves. But it is not lawful for us to believe that God is affected in one way when he is at rest, and in another when he operates; for he is not even to be said to be "affected," as though something should come to be in his nature that was not there before. For he who is affected undergoes something, and everything that undergoes something is mutable. Let no sluggishness, then, no sloth, no inactivity be thought of in his rest, just as neither labor, effort, nor industry is to be thought of in his work. He knows, at rest, how to act, and, acting, how to rest. He can bring to a new work a plan that is not new, but everlasting; nor, by repenting because he had previously ceased, does he begin to do what he had not done. But even if he ceased before and operated afterward — which I know not how it can be understood by man — this at least, without doubt, which is called before and after, existed in things which before did not exist and afterward did exist. But in him, no later will changed or took away an earlier will; rather, by one and the same everlasting and immutable will, he both brought it about that the things he founded should not exist for as long as they did not exist, and that they should exist afterward, when they began to exist — hence perhaps wonderfully showing to those who are able to see such things how little he needed them, but rather founded them by his gratuitous goodness: he, without them, from an eternity lacking a beginning, remained in no less beatitude.»

You will ask 2° whether to be immutable is proper to God.

I answer affirmatively³.

Proof. Every creature is mutable, either according to substantial being, as sublunary bodies; or according to local being only, as the heavenly bodies; or according to order to an end and the application of its power to diverse things, as in the angels; or according to various accidental perfections, as are all created, finite, and imperfect beings; or finally, according to being and non-being, as again, universally, all creatures which are in the power of the one creating and conserving them, as regards being and non-being. But God is mutable in none of these ways, as will be clear to one running through them one by one, and as is clear from what was said in the first question. Therefore.]